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    It From Bit: The Case Of Gravity
    By Johannes Koelman | January 7th 2010 11:39 PM | 126 comments | Print | E-mail | Track Comments
    About Johannes

    I am a Dutchman, currently living in India. Following a PhD in theoretical physics (spin-polarized quantum systems*) I entered a Global Fortune

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    Three weeks of speculations have come to an end. Since this morning Verlinde's paper is available on arXiv.

    I encourage you to give it a try. The article is well written and the math is limited to fairly basic stuff. This combination makes it a relatively easy read. Granted, the paper requires some more gray matter cells being active than the average “Hammock Physicist” blog entry, but for an average Hammock Physicist reader probably not by an insurmountable amount.

    The crux of the article can be summarized in one sentence:

    If it smells like entropy, and it behaves like entropy, it probably is entropy.

    As was suggested before, one can consider Verlinde's starting point to be a reversal of concepts like the Hawking temperature of black holes and the Unruh effect. Let's take the black hole temperature as an example. The black hole temperature is defined at the black hole horizon, and since Hawking's groundbreaking work we know it is proportional to the gravitational acceleration at the horizon. Now Verlinde reverses this. He asks us to consider the gravitational acceleration at the horizon as resulting from the horizon temperature.

    Subsequently, Verlinde takes a deep dive: if an acceleration is proportional to a temperature, it has all the characteristics of an entropic effect. Entropic acceleration results from the tendency of a system to evolve such that there is an increase in the minimum number of bits required to describe the system in all its details. Could it be that gravitational attraction results from nothing more than a growth in number of bits required? Verlinde argues that such is indeed the case. Key is that one needs to follow a holographic approach with all bits describing reality residing at holographic screens.

    Erik VerlindeI think the relation to entropic effects is clearest in one of the Newtonian scenarios Verlinde considers: a given matter distribution that creates a gravitational potential. Verlinde requires the holographic screens to coincide with equipotential surfaces, and arrives at the conclusion that the bit saturation (the number of bits required to describe the system divided by the number of bits available on the screen) equals where  represents the Newtonian gravitational potential. This bit saturation is a positive number that vanishes at large distances. If one shrinks the holographic screen whilst ensuring it keeps following the equipotential surfaces, the bit saturation keeps growing until it reaches a value of unity at which the screen is saturated with information. It can not shrink further, a black hole hole has formed with the screen representing its holographic horizon.

    Again, you have to reverse this thinking. When doing so, the picture that emerges is that of a gravitational attraction (acceleration defined by a gravitational potential) that results from a tendency of physical systems to evolve such that the holographically available bits saturate with information. This tendency towards bit saturation is an entropic effect, that we experience as gravitational attraction.

    Verlinde goes further than Newtonian gravity. He discusses inertia, the equivalence principle, the Einstein equation, and also gives some hints towards implications for string theory.

    The paper inevitably has somewhat a handwaving character, and provides a direction rather than a full theory. Yet, the direction is clear, and points to a novel horizon (pun intended) that is unexplored. I do consider Verlinde's arguments to be convincing. Verlinde is 'on to something', and it would not surprise me if in a short time frame we will witness a flurry of activity in this area.

    A few more critical remarks: in most of the examples, I do not think the sign of the entropic force comes always out very clearly. Related to this is the question: how is the inside and the outside of a screen defined whilst avoiding any circular reasoning, and how to get a change in sign between attractive and repulsive effects. I am convinced that within the existing framework these questions can be answered in a satisfactory fashion. These matters are of paramount importance if one starts to address issues like: can one use this entropic approach to eliminate the need for dark energy ? Other more philosophical questions center around the emergence of time (and the good-ole 'arrow of time') from this entropic approach.

    And, of course, the million-dollar question is: “what laws govern the bit dynamics on holographic screens?”

    To be continued...

    Comments

    "Related to this is the question: how is the inside and the outside of a screen defined whilst avoiding any circular reasoning, and how to get a change in sign between attractive and repulsive effects."

    I think Padmanabhan's idea of using simple local Rindler space transforms for describing screens looks promising. (I have not yet read Verlinde's paper)

    Rob

    Hmm,

    So it seems he's saying that gravity is an entropic force mean that it's a macro force that would arise given any reasonable micro theory of the forces. If so, does this mean that gravity could break down at the micro level, or even the macro level given various low-entropy conditions?

    Funny thing - I used to toss out this rhetorical question occasionally: "How much does a bit weigh?" Then a couple of years ago I learned (from a SciAm article) that a bit doesn't have mass but does have area - about two Planck lengths squared - based on conservation of entropy on a black hole horizon. Now we are going full circle! :)

    I'm dying to read this article by Verlinde, but unfortunately I'm having trouble accessing the PDF file. I don't know if the server is having problems, but the abstract was intriguing. So now it's become imperative that I read this article! LOL ;-)
    Am I missing something here or is this looking at the same equation differently, like saying a*b=c and c/b = a, where a and c are known values. It is interesting math but I think it’s just math masquerading as new physics theory.

    Even if so, sometimes such a change of perspective is just what's needed to break open a field.

    Well, a change of view is sometimes very good. If we went from a/b = c to a = cb then we can suddenly model realities in which b=0.

    Thanks for posting this! Looking forward to reading this article. I often think about "it from bit" since taking a gravitation course from Kip Thorne back in college, and it really feels like the time is ripe to be making more progress here.

    You took a course from Kip Thorne, Sho? Cool! And I agree with you that the time is ripe to be making more progress.

    I can see that this article is generating a lot of heated discussion. That's a good thing. Can't wait to read the paper, which I finally was able to download to hard drive.

    Best,
    Eric
    Yeah, although back in those days, I was kind of a goofball and didn't pay much attention to school. If I had it to do over again, I would be in that class every single day, taking copious notes!

    The reason I mentioned Kip Thorne was not to name drop, but because the first time I heard the phrase "it from bit" was, I think, in a section (an afterward or something?) of the textbook that he wrote along with Misner and Wheeler. It's Wheeler's phrase, right?

    My memory is foggy, but I remember three ideas were presented in that section - "it from bit," something about the relationship of observers and the universe (the "U" with an eyeball picture), and something I can't remember.

    I'm hoping that we can live through another radical revolution in the fundamentals of physics along the lines of the early 20th century. To me, things like the holographic principle hold more clues to a fundamental shift than, say, string theory. It will be interesting to see how this all plays out.

    Yes it should, Sho. Even though it's consistent with string theory, it's going to have some impact on it, which I think is good. Like the paper says, string theory resolves a lot of problems, but not all of them. I'm very excited about this after having read the paper in its entirety.

    P.S.

    If it's any consolation to you, I was a bit of a goofball in my first couple of years in college. If I had it all over to do again, I would have paid better attention and taken better notes too. So don't feel bad. ; )
    So, if gravity emerges from (very roughly) "the flow of information", what would happen if you could "control" how much information flows between two points? In particular, could you use a meta-material (negative index of refraction) to create a "cloak" around an object? Would the gravitational attraction between the object within the cloak and the objects outside the cloak decrease? And what about a "theoretically perfect meta-material mirror", one that was capable of operating from DC to infinity?

    Verlinde claims that his derivation has very minimal assumptions, and does not include this "the world is a hologram theory" among them. If gravity can truly be explained in this manner, then we need to think more about the implications of a holographic universe...and idea that simply shatters our entire notion of existence. In trying to understand more about what this holographic theory is, I came across this website:

    http://www.crystalinks.com/holographic.html

    Is this the same holographic theory???

    Stuart,

    The holographic principle has been introduced in 1993 by Gerard 't Hooft from Utrecht University, and has since been extended by 't Hooft, Leonard Susskind and others. It doesn't claim 'the world is a hologram', but states it should be possible to describe a 3D volume fully by a theory on its' 2D (light-like) boundary.

    The site you mentioned above (based on a book by a Michael Talbot) gives a rather mysticized/spiritualized interpretation of that principle. However, 1/3rd down that page is a copy of a 2003 article from Scientific American which is quite good.

    Also, see: http://en.wikipedia.org/wiki/Holographic_principle.

    Here is a direct link to the Scientific American article:

    http://community.livejournal.com/ref_sciam/1190.html

    It was written by Jacob Bekenstein, one of the founders of black hole thermodynamics.

    That sounds like an instance of the generalized Stokes' theorem...

    What is flowing "through" the surface? Information?

    What is an "entropic force"? There isn't any such thing. There are the usual microscopic forces which create equations of motion, and with notions of dynamics of many degrees of freedom, phenomena like entropy emerge when you have a characteristic decorrelation timescale (e.g. reciprocal of the Komogorov-Sinai entropy rate) substantially shorter than the measurement timescale.

    Verblein: "A single polymer molecule can be modeled by joining together many monomers of fixed length, where each monomer can freely rotate around the points of attachment and direct itself in any spatial direction. Each of these configurations has the same energy. When the polymer molecule is immersed into a heat bath, it likes to put itself into a randomly coiled configuration since these are entropically favored. .... The statistical tendency to return to a maximal entropy state translates into a macroscopic force, in this case the elastic force."

    What does it mean "it likes" to do anything? It is mechanical vibrations mediated by electromagnetic interactions.

    A "heat bath" is an emergent macroscopic phenomenon resulting from microscopic interactions: combining laws of mechanics of atoms (quantum or classical) with essentially electrostatic scattering (nonlinear) between you get chaos. Chaos in the motion of large collections of atoms---consisting of interacting charges---is unavoidable.

    In statistical systems, with particular and specific technological efforts, one can modify the specific microscopic chaos-creating phenomena by manipulating the microscopic system appropriately.

    Of course, general thermodynamics is the default state which happens most of the time. But if gravity is only macroscopically emergent, does this mean that if we arrange the microphysics in a peculiar way we could apparently alter what would otherwise be interpreted as fundamental laws of gravity?

    To be blunt: can we make warp drive without requiring discovery of new fundamental physical forces?

    A related question: is conservation of energy (define appropriately) a universal microscopically conserved phenomena, or is it a macroscopic emergent property like thermodynamics---in which case there might be technological ways to avoid it, at least temporarily in a small part of space?

    Matt: You ask:

    Of course, general thermodynamics is the default state which happens most of the time. But if gravity is only macroscopically emergent, does this mean that if we arrange the microphysics in a peculiar way we could apparently alter what would otherwise be interpreted as fundamental laws of gravity?

    Doesn't that last sentence map to:

    But if temperature, pressure, and heat transfer are only macroscopically emergent, does this mean that if we arrange the microphysics in a peculiar way we could apparently alter what would otherwise be interpreted as fundamental laws of thermodynamics?

    Much as we'd all like to modify one or more of that trinity, it still seems to hold at all scales and I haven't heard that Maxwell's Demon has been spotted or constructed yet. By analogy, gravity as an emergent phenomenon doesn't necessarily mean there's a way to tweak the microscopic arrangement of gravitationally-interacting components to rewrite it.

    Similarly, if all the microscopic physical pieces obey the conservation of energy, their combinations will, too. As for temporarily avoiding it locally, isn't that what virtual particles in the vacuum do? Exist for a short enough time (before mutually annihilating or interacting with other stuff in a way to eat some mass/energy and/or quantum numbers to render one or both of the pair real) that their mass-time product comes in under the uncertainty principle limit - the only regime where mass-energy seems to bee less than constant.

    If it smells like entropy, and it behaves like entropy, it probably is a Boltzmann gas... We simply cannot have an abstract entropy quantity existing as such without underlying physical system (usually inertial particle gas or fluid), which maintains the laws of statistics. Emergent phenomenon is just another word for Aether model, described by gas (thermodynamics) or by fluid (hydrodynamics) models.

    Newton himself believed, gravity force is indirectly proportional to distance with compare to R. Hooke, who claimed the inverse square law on background of former Alhacen's work. Just the Aether model of his friend Fatio de Duillier convicted Newton to change his opinion on behalf to inverse square law. Duillier's model was later extended by Le Sage. So far we have no other working theory of gravity. The unability of scentists to distinguish trivial particle system beneath all these noble ideas about thermodynamics, entropy and emergent holographic scenarios is striking. Even worse, it's a sort of modern religion.

    The reason that impulse theories of gravity are discounted is because they predict behavior which doesn't happen out here in the real world. In particular, they predict that the planets should suffer severe drag-induced spiral motion terminating at the Sun far earlier than the present day. Since we're all still here, Le Sage doesn't work.

    You're right, but entropic theory of gravity faces the same problem, as the entropy of Universe increases gradually. After all, from relativity theory follows the same conclusion: all geons should collapse into singularity undeniably. With compare to relativity, quantum gravity theory predicts, all quantum wave packets of free particles should dissolve into infinity instead. So where's the truth?

    Well, we shouldn't forget, the second seaming problem for Le Sage theory is the "energy and heat issue". As Maxwell and Poincaré showed, inelastic collisions lead to a vaporization of matter within fractions of a second.

    Aether Wave Theory faces this controversy by consideration of dynamic equilibrium between gravitational collapse following from momentum issue and pressure of radiation, following from heat issue. This assumption turns both disadvantages of Le Sage theory into its strongest point.

    This is all interesting stuff. This seems related to Ilya Prigogine's work in his book "The End of Certainty", where he talks about entropic effects on time and the arrow of time.

    It is also interesting to note that all of this is coming about 100 years after the work of Einstein, by building upon observed phenomena (Hawking radiation) and recent advances in understanding.

    Submission histories:

    On the Origin of Gravity and the Laws of Newton
    http://arxiv.org/abs/1001.0785
    Submission history
    From: Erik Verlinde P [view email]
    [v1] Wed, 6 Jan 2010 20:45:59 GMT (504kb,D)

    Equipartition of energy in the horizon degrees of freedom and the emergence of gravity
    http://arxiv.org/abs/0912.3165
    Submission history
    From: T. Padmanabhan [view email]
    [v1] Wed, 16 Dec 2009 15:36:40 GMT (6kb)
    [v2] Mon, 28 Dec 2009 08:52:12 GMT (9kb)

    The stuff about information being involved reminds me of Frederick W. Kantor's "Information Mechanics". He also attempted to derive things like gravitation from first principles. Perhaps these two works should be compared.

    It is interesting stuff, although I am not convinced of his method. I have really yet to see evidence for the claim: "If it smells like entropy, and it behaves like entropy, it probably is entropy.", beyond equations "looking alike".

    Looking at the proposal, he derives the Newtonian laws from Information Theory (IT), but IT is itself derived from Newtonian mechanics -- he even mentions that he is using a 2pi constant because it results in the Newtonian equations (without having a reason for the 2pi value). For the Einstein relativistic equations, he is basing them on a relativistic Gaussian equation (which IIUC was derived from General Relativity).

    An interesting aspect of this theory is that it could lead to a Quantum Mechanical interpretation of GR that can fit in with the other forces. Does anyone know if this resolves deficiencies in the two theories (e.g. the center of a black hole being a singularity)?

    Fun paper to read. There are a lot of interesting hunches in here, and it will be interesting to see if it leads to anything.

    Some thoughts -- my physics is rusty so perhaps smarter people can help me through this:

    1) Not sure Verblein is successful in postulating ideas that amount to 'space' emerging out of the theory. The non-relativistic case depends on the Newton potential (which is defined in a fixed coordinate system), as well as gradients of those fields, which are themselves problematic. The relativistic version depends on Killing fields, which I suppose you could talk about as "generating" space, but then again, you could say the same thing for standard old general relativity, right? Mass and energy are the sources of a field that defines a metric, right? And in this formulation, there is now an entropy (that takes the place of mass and energy) which looks a lot like a scalar field to me, and there are some equations that generate metrics. Is that any more "spaceless" than standard general relativitiy?

    2) It seems that a lot of the heavy lifting in this paper is done by equating holographic screens with equipotential surfaces of the Newton potential. Does that strike anyone as fishy?

    3) I basically don't understand the Unruh effect (never hear of it before reading this article) but from what I can figure out, it feels awfully weird to (a) reverse the equation and read it backwards (temperature causing acceleration, not the other way around), and (b) to interpret that as being the source of inertia, rather than to simply call it a "force", which is what you do whenever you discover something else that causes acceleration. If the idea is that this is special because it is a force that is associated with inertial mass? If so, why is this formulation special, when compared with other formulations of gravity?

    To summarize my takeaway from the paper, it feels like the main takeaway is "maybe entropy causes mass rather than the other way around", and that this result comes from (a) a microscopic formulation using the concept of an "entropic force" and (b) piecing together a bunch of equations relativity + the holographic principle and choosing to read them backwards (i.e., temperature causes acceleration, and not the other way around).

    I'm probably missing stuff here because my knowledge of this stuff is rusty. Am I missing stuff here?

    Good thoughts and questions, Sho. My physics is probably more rusty than yours, so I will wait for someone smarter and more knowledgeable on these matters than either of us to comment.

    It is indeed a fun paper to read.
    These are certainly well-informed questions.

    I think 1) and 2) may be answered (to a degree) by the discussion Erik Verlinde has added to his webpage, to clarify the logic of his paper: http://staff.science.uva.nl/~erikv/page18/page18.html

    The Unruh effect is still a hypothesis, although firmly rooted in black hole thermodynamics as described by Stephen Hawking. The effect has been described to me as: "if you wave a thermometer in empty space, it will heat up". LOL

    The paper by Verlinde *very* carefully builds up its' concepts in the first few chapters, argueing step-by-step towards the 'Gravity as an emergent phenomenon' theses. Because it gives a new and different account of Inertia and Gravity, it would not suffice to just give the equations. It needs to clarify the ontology - which concept is based on what etc... A good read indeed!

    Cheers!

    Thanks for the link, Bob. The Web page certainly did help to better understand the logic of Verlinde's paper.

    Best,
    Thanks for the link. The web page definitely helps clear up some of the questions I had.

    It still feels like Verlinde is engaging in quite a bit of handwaving (not that this is a bad thing. I think he would probably say the same thing).

    The argument, as stated in the paper and as clarified in the web site, is to start by imagining a holographic surface with a collection of possible states, and through some tricky reasoning, generating equations that look suspiciously like newtonian equations of motion for a variable 'x', which he identifies as a position in the direction normal to the surface.

    This is an enticing result, but to me, it still doesn't feel like a fully spaceless theory. A spaceless theory would probably need to throw out a notion of a "holographic surface" and start talking about states in the absense of space. Either that, or it would need to motivate the relationship between the microscopic states and the interpretation of these states as being related to "surfaces" in some way.

    Anyway, this is not a knock against the paper in any way. The paper didn't claim to solve all the mysteries of the universe. I'm just trying to make sure I understand what is and what isn't being claimed by the paper.

    Hello, I am not a physicist, but the topic is quite interesting too me. I am having a bit of a hard time conceptualizing this, and was wondering if someone could tell me if I'm on the right track...

    Okay, so at first blush this seems totally counter intuitive. The largest positive entropy event was the big bang (correct?), which was things flying apart, not coming together. So how could moving things closer together increase entropy. BUT, it sounds like that entropy isn't measured by number of bits (which I thought) but rather bit saturation/density on the holographic plane. So, now there two ways to increase entropy, gain a bit, or shrink your area while maintaining the same number of bits. So, bringing things together, would shrink the plane, so it happens. There's no stopping that entropy! That's all even think I get.

    But that still doesn't make complete sense, as we know the universe is expanding, so some how you have local holo-plane contraction (I didn't even think there could be such a thing) with universe-wide holo-plane expansion ... that doesn't make sense, so maybe I'm wrong about the whole thing! help!

    Intriguing theory. Doesn't only feel like entropy, but it also feels like 'something is the air' and that Erik Verlinde is close to a fundamental break through.

    I have been playing with all the formulas that provide the ingredients for this seductive gravity stew and tried some very wild combinations. One is the (probably crazy) assumption that even the fact that the speed of light must be constant for all observers, could be an emergent phenomenon from the way bits are stored on a holographic screen.

    1. Start with Unruh and isolate c: (with h = h-bar)
    c = a/T * h/(2pi k) (so the acceleration of the screen divided by its temperature induces c)

    2. Take the equipartion theorem and isolate T (with N as the max possible number of bits on a screen):
    T= 2E / (Nk)

    3. Calculate N by dividing the screen surface by the Planck area ((Gc^3)/h)
    N = (4pi r^2 h) / (Gc^3)

    4. Inject 3 in 2 and 2 into 1 and add E=mc^2 to obtain:
    c^6= (a/m) * r^2 * h^2/G

    Since h and G are just constants, the outcome of (acceleration divided by mass) multiplied with the squared radius from the mass to the holographic screen surface, must always be constant.

    Every force should be entropic not just gravity because one should be able to make a Supergravity theory from an Entropy functional analogous to Verlinde's construction of General Relativity. The Sugra form fields are the other fields. It should also be possible to make a string theory by finding an entropy functional that would generate the fields on the string worldsheet (a 2d sugra). If it has a Lagrangian there's probably some way to define an entropy functional. Since this is physics without a Lagrangian or Hamiltonian, there must be some new quantization scheme. We can only pray it involves working directly with von Neumann density matrices which is a prettier way of doing QM and my hunch is that it does.

    Gents,

    Prof. Verlinde has added a discussion to his webpage to clarify the logic of his paper, since it has been misunderstood and misrepresented in blog reports. Please take a look:

    http://staff.science.uva.nl/~erikv/page18/page18.html

    It might answer some of the questions above. On my personal note, it is probably a good idea to actually READ the paper before commenting on it... maybe read it twice. :-)

    If mass emerges from entropy then what is the implication for the existence of the Higgs boson - which would explain the (microscopic) origin of mass? Do these new insights imply that the Higgs field is emergent too? Conversely, if the Higgs particle is actually found, would that be at odds with the notion of gravity as emergent force?

    IMHO, there has always been a fundamental disconnect between how the relativists think about the relationship between gravity and inertial mass -- gravitation is not a force, things just move on geodesics -- and how quantum mechanics think about gravity and inertial mass.

    You're right that this would put the two views even more at odds with one another, but I think the discrepancy between the GR and QM views of gravity is already there in the community. You can feel it practically dripping off of the first few paragraphs of Verlinde's paper.

    Based on Verlinde's additional explanation that he published on his website today, I've tried to summarize the concept in a single diagram. Not sure whether I have grasped the main concepts and therefore open to any feedback/corrections!

    [URL=http://img33.imageshack.us/i/gravitropy.jpg/][IMG]http://img33.imageshack.us/img33/6677/gravitropy.jpg[/IMG][/URL]

    This is a better link. Mea culpa.

    http://img33.imageshack.us/img33/6677/gravitropy.jpg

    I think of the bits of information as the expression of real and virtual physical processes that are occurring in the space between the mass centers and the holographic surfaces. In this representation, there is a limit on information capacity that is determined by the ability of space to transfer data rather than the ability of a holographic surface to contain the data.

    The holographic surfaces can be constructed anywhere, but the data transfer continues in a certain place even if the hologram has not been constructed in that location. At an event horizon of a black hole the data saturation is just a way of saying that the space has become degenerate.

    Considering the other types of old stars that have left the main sequence, degeneracy is a familiar characteristic that is particular to the description of each type of star. If red giants are becoming electron degenerate in the core, then white dwarfs are proton degenerate, and neutron stars are neutron degenerate. All of these are physical processes, not just some accounting system to keep score.

    In the case of newly forming black holes, there is nothing left to become degenerate except the Zero Point oscillators of vacuum energy.

    The question about data transfer is restated to ask how much information the Zero Point can contain and transfer through the surface segment that is one or two Planck lengths squared.

    I find a lot of importance in the holographic work Verlinde is doing. It is a path forward toward uniting cosmology with quantum mechanics, and that whole field of work is long over due.

    To make a guess at the next steps, it seems likely the difficult question of how much vacuum energy there is, what form it takes, and how it relates to the cosmological constant will enter into a debate where there are very strong opinions and very much opposing views.

    Verlinde has been very clever in finding a path forward without making a frontal assault on some very formidable opponents. He managed to include all of the essential features without saying exactly how he intends to use them in extensions of the work. His treatment of the physical processes as a data processing operation is rather funny, but it also moves the science a step forward without creating a big target for opponents to shoot at.

    The choice of Temperature and Entropy to describe the thermodynamics is another way to out maneuver the opposition. In the physical world thermodynamics can be described by any two state variables. Some pairs are more popular than others. Verlinde chose a pair that is fully described without making a statement about the magnitude or structure of vacuum energy, or how it transfers data. The hologram can also be thought of as a maneuver of the same type.

    Another maneuver was to develop the time variable in a physical system that did not contain any space to begin with. Since space is not a fundamental basis for the theory then there is no need to define the vacuum of space and it's physical properties.

    There are in fact quiet a few other maneuvers to edge out the competition in Verlinde's paper. One of the big choices was to demonstrate Newtonian gravity instead of general relativity. Newtonian means nearly flat space with science that is not contested.

    The total result was a prelude to some really big advancements that are coming in the unification of cosmology with quantum mechanics, and our understanding of fundamental laws about space, time, and energy.

    Pragmatics is the part of linguistics that studies what words *not* to use ;-)

    Maybe this explains why he took so long to write down these ideas. And I agree, it is a mighty teaser. We all want to see more.

    But even this little and abstract reasoning is attacked with
    "This kind of backwards logic runs rampant in physics, although luckily usually just on the fringe. I am sure this hype will blow over soon, when people actually take the time to read the paper instead of just listening to the author’s claims of “significance”."
    Just one rant of many by someone calling her/himself Camel

    Maybe Verlinde learned a lesson from Darwin (200th anniversary), who sat way too long on his theory for exactly the same reason.

    Rob

    I'm afraid that my knowledge of physics amounts to a few semesters passed half-asleep at college, struggling to balance equations to barely survive, so I ask your forgiveness in advance if I sound too naive...

    Verlinde's paper was definitely "readable" even for me. Information Theory is something that is part of my computer science background, of course, as well as the relationship between entropy and IT. At least that was familiar. The "readability" of the paper comes mostly from the easy, elegant way of describing what may very well become a GUT, or at least the foundations of a GUT. I was definitely excited!

    Some corollaries of Verlinde's paper were quite intriguing. One, of course, is that he completely discards the need for "forces" (and "force fields"). This is a fascinating concept. Interactions can be fully described by his theory; so you don't need particles, only temperature and information to define motion (acceleration) and thus we get presented the inverse model: gravity or inertia are not forces that cause acceleration, but acceleration is provided by "bits in motion" that we perceive as forces. So, goodbye graviton, but also (possibly) goodbye Higgs boson, and, well, goodbye the whole mess of the standard model (which I will be glad to see gone, to be honest). He also describes a much more reasonable way to tie the microcosmos to the macrocosmos, mostly by making very few assumptions at the micro level, but showing how Newton and Einsteinien mechanics can be derived from those. I'm reluctant to say "goodbye quantum mechanics" — that would be way too bold — but certainly "goodbye strange unexplained phenomena that are theoretically possible in QM even though we might not observe them". QM tends to demand a huge conceptual leap between the micro and macro. But — here is the crux — QM does offer predictions and ways to confirm those predictions. Verlinde is honest enough to say in his paper that it's too early to make predictions with his theory, although he hints that his next paper will be about cosmology, which is natural, since that's his background really — from black holes to superstring theory. His new theory tends to offer alternative explanations, and no wonder he's excited about applying them to his own field of study.

    In my mind, I think it'll be even more interesting if the theory is turned to atomic interactions in molecules. If Verlinde's physics can model the way atoms combine in molecules, explain chemistry reactions, and does all that just by shuffling bits around holographic screens and measuring gradients of entropy, I'll be fascinated — and QM might be given a serious blow. Verlinde already incorporates an uncertainty principle (based on the bit density on a holographic screen describing a single particle in space).

    Again, forgive me my ignorance, and please let me know if I have gotten Verlinde's assumptions utterly wrong. I'm just excited that, if Verlinde's new physics might come to something, I might finally understand the underlying physics in this 21st century, while having spent the 20th century in utter ignorance on how things actually work :)

    Hi Luis Miguel,

    Although I share your interest, and I'm enthusiastic about this paper as well, maybe it is wise to point out that Verlinde *IN NO WAY* claims to offer a grand unified theory here, or seeks to supplant either Standard Model or string theory physics. He's actually an important contributor to (matrix) string theory.

    What Erik Verlinde does claim is already in the paper, no less, no more.

    There is a real risk in new developments such as these, that media hysteria and hype takes over from objective contemplation and critical thinking. Of course 'critical' should not mean an outright dismissal of new ideas or lines of reasoning, but a degree of open mindedness - without being so open minded that your brains fall out ;-)

    From a Standard Model perspective, there may be an excellent reason now why the quest for unification with quantumgravity has not been successful - because gravity might not exist as a fundamental force after all. Also, Verlinde mentions in chapter 6.2 a variety of ways in which emergent gravitation might be in accordance with string theory.

    Cheers!

    IIUC, Quantum Mechanics (QM) describes the force carrying particles (Bosons) in the standard model. These particles travel at the speed of light and have no mass (and therefore energy), so do not apply to the warping of space-time described in General Relativity (GR).

    GR applies to energy-mass, and thus the mass carrying particles (Fermions) in the standard model. These create gravity by warping the space-time geometry around them in the GR interpretation of gravity.

    Many approaches to moving GR into the QM world have been to describe GR as a particle exchange of 'gravitons', which are thus Bosons. The problem with these approaches is that they fail to understand that the Fermions are themselves the carriers of the gravity 'force', as they curve space-time, and have failed to bridge the disconnect between the two theories.

    What is interesting about Verlinde's approach is that he has come up with a model originating in information theory and thermodynamics that have Newtonian Mechanics and GR fall out of it without pushing gravity-as-a-force that other approaches have tried to do. Furthermore, this interpretation builds upon our modern understanding of GR (Hawking radiation) in a way that is likely to be compatible with Quantum Mechanics.

    This is just laying the foundations for further work such as understanding how this will fit with QM. If a combined QM-Verlinde model is created, then that will be a General Universal Theory in that it will be a complete representation of the standard model instead of the current two theories (QM and GR). It will have also gone further as well, by pulling in thermodynamics.

    Right, reece, that's indeed what shall be worth seeing... Verlinde's paper doesn't touch QM directly, and I understand that the major reason is because his work is mostly focused on the other extreme: cosmology, black holes... So now someone coming from the QM side of it might take a look at what they can do with his model. Maybe they can reasonably prove that there is no possible relation between both, which would be a pity. Or there might be a revision of "quantum-information" theory that gets pushed ahead. Or — which would be fantastic — an explanation that doesn't require QM at all ;) But all that, of course, is just my wild speculation and not intended or implied in any of Verlinde's articles or comments, of course.

    Thanks, Bob, I truly appreciate your comment and the explanation. You're obviously quite right, but it's nice to speculate where this might lead us... :)

    If the Holograms have a physical existence, they must move at light speed or be assigned a rest mass. There are no other classes of physical objects reported anywhere in science.

    To move at light speed would compromise the equipotential calculation method, and there is no mention of a rest mass, so I regard the holograms as a type of mathematical abstraction, that happens to describe some physical things correctly, but has no fundamental physical existence in space. Then gravity does not arise from the information in that type of hologram, but by physical processes that the holographic data is describing.

    There are other ways to present holograms in ways that do allow them to have a physical existence. The simplest construction is a hologram that moves at light speed in every direction that results in an increase of the surface area. The equipotential requirement might also be met or not missed by much, if the degrees of freedom are not constrained by any thing other than the physical space.

    Classical science already has some physical objects of this last type. It is called a wave front, and can be found in a long history of optics and also in quantum mechanics since the time of Richard Feynman.

    One place where physics of wave fronts becomes important to everyone is in the air gap of an electric motor, between the moving magnets. It is easy to show from well established science that when a motor generates enough power to lift a one kilogram mass on the surface of the Earth, the power of the wave front in space between the magnets is very nearly 3,000 megawatts. The vacuum promptly recovers the energy, and is not even slightly inconvenienced by the exchange. That much power is not created by counting bits of data on a far away surface.

    Combining the hologram with physics of a wave front would be a fundamental advancement, and not a far stretch of the imagination for a large part of the scientific community.

    In Verlinde’s paper the hologram could be thought of as a brief snap shot photograph of what was happening in a part of real space.

    Now photos are a collection of data bits, storage, and transfer of information, although in previous times photos have been regarded as a gateway into some alternative reality. Taking the photograph of a person does not give life to a person, except maybe for the smile that might not otherwise occur. Using the word “Taking” instead of a term like “Collecting” implies an intrusive procedure that was debated in the early days of photography. So something of a feed back loop is allowed for modifying a measurement, but not as the primary cause of a physical existence.

    The photograph analogy is a good one and opens the way for development of a more comprehensive theory of cosmology based on a series of holographic snap shots in a moving wave front. Verlinde has assembled the components he needs for such an attempt, but without an explanation of how they fit together. Things like equivalence and partition occur in his paper and again in his explanation. These are bits of data that describe real physical things, but not sufficiently well in the existing science, to reconstruct a moving wave front.

    Eventually I would like the see the description of the moving wave front, but for now we just get a few photos of it.

    In the electric motor example, the reader should realize that the magnets have polarized the vacuum by shifting the partition of energy to express an electromagnetic excess compared to the equipartition of flat space.

    In present thinking, the strength of gravity is weakened in the polarized field to off set the power flow that is diverted to the magnetic wave front. Some claims of that type have been published, but the percentage change in gravity is small for the power exchange of 3000 megawatts.

    When the wave front has passed by a location the space partition quickly reverts to normal at that place, demonstrating that equipartition is the equilibrium state of flat space that is not under stress..

    Verlinde showed that the departure from equilibrium can also be represented by thermodynamic functions. He put the force F into the partition Z in one place and into the internal energy E in another place. He actually presented the omega function in a way that expresses both concepts at the same time, and demonstrated how the thermodynamics derive from the partition.

    Erik Verlinde has added info on: the essential new points of the paper.

    http://staff.science.uva.nl/~erikv/page18/page18.html

    It must NOT be easy being an International Superstar of Science! I do hope the good man has some time left to work on theory, with all this bloggery business ;-) ;-)

    Cheers!

    Johannes Koelman
    Yes, it seems Verlinde has discovered the power of blogging. ;)

    Verlinde's own weblog does help getting the idea across. I think these are exciting developments. I'm now not referring just to the theory itself, but more generally to the way the larger public can participate in interesting new scientific results and developments via the 'bloggosphere'.

    I am now traveling, and I have little time to react here. But next week I will likely meet Verlinde in person, and I am arranging an interview with him. Watch this space...
    Hi Johannes,

    That is good news - please do bring our encouragement across, as I'm sure you will.

    This type of 'interactive public outreach' is quite new and carries lots of promise. However it also requires moderation, wisdom, and even somewhat of an elephants' skin to make it succesful!

    Among the general public (and among professional physicists sometimes) there are lots of people who want a new idea or proposal to be categorized as 'RIGHT', 'WRONG' (or 'NOT EVEN WRONG' for tri-valued logic...) within the shortest possible time, and they attach the full weight of their egos to such a position. Once they have given their opinion, or their feedback, they will not waver in that position for fear of losing prestige.

    If a new idea requires the audience to suspend belief in certain (quite intuitive and deeply engrained) concepts about physical reality, there is a very fine line to tread in upholding their trust and gradually building up a new and somewhat different 'language' and conceptual framework.

    I think the paper, as well as the additional notes, are to be commended in gradually introducing the main idea to the professional as well as the general reader, while making clear it is still a 'journey of exploration'. The preliminary results ought to convince people in the field it might be quite worthwhile to embark on such a journey...

    There's lots more to write about this - but later, i'm too tired and short for time. Maybe I'll drop you a personal message. :)

    Cheers!

    Aitch
    Good Luck with the interview! Great thread too, excellent contributions, thanks I won't spoil things with my current questions....I need more absorption time Aitch
    Hank
    Have him do some guest posts here.   Certainly the audience seems to like your work about him.
    There is quite a number of "this is not physics" and "The Verlinde hype will blow over soon" responses, often by people who seem to have some difficulty with grasping the problems of integrating gravity with the standard theory. It is good he is enthusiastic about his theory.

    With blogging he will be able to improve his presentation as the bloggosphere seems to be able to, not only to find all bugs, but also to generate every crackpot response of misunderstanding

    For me, a layperson, a first definite hint that something was really amiss with gravity as a fundamental force was the fact that any single graviton detector must be smaller than it's own Schwarzschild radius. Which tells us that there is no way to detect a single graviton. And by definition, undetectable particles do not exist.

    Rob

    Extreme news in a science.
    Gravitation, UFO, physics.
    http://viictor-viictor.blogspot.com/2010/01/gravitational-interaction-fo...

    Continuing the previous comment on the electric motor.

    When a force is transmitted to a distance, even a small distance through space, the power that carries it is the well known equation:

    (G.1)....... P = c F.... where c is light speed.

    Then it is easy to say how much power the vacuum is lending to carry the wave front. The equation can be applied to gravity fields also. Near the earth the vacuum is lending nearly 300 megawatts per Newton of force. There is no scientific dispute about this, that I know of. It is simply ignored in a lot of theoretical work, because the power level is too high for easy comprehension.

    The vacuum is very efficient in continually recovering the energy according to the time limits of Heisenberg's uncertainty principle. There is no net gain or loss of energy in bending of space.

    Vacuum polarization by proximity of a mass is the same thing as gravitational curvature of space. In this representation the gravity field has no real physical existence other than the shifting of partition in the vacuum energy, in favor of the gravitational potential.

    It is the vacuum that transfers the information of partition from one place to another at light speed in all directions.

    That information can be displayed on a hologram, but the hologram is not the source of the information or the vehicle that transmits the data.

    Considering the amount of vacuum power that circulates to support a gravity field, the hologram is not able to express the total information of the action. It only expresses the net result that occurs at the location of the hologram.

    If the natural laws of physical processes were derived from bits of information written on a holographic surface, then our technology would be sufficient to rewrite the laws of nature and change the physical constants. Something like that doesn't happen.

    The natural laws are derived from the structure of time and space in the vacuum. It is the vacuum energy that enforces the laws of nature. Vacuum energy is very large, but not infinite. It can be calculated from the measurable properties of space. All the power we can generate is miniscule compared to the vacuum energy. That is the reason we cannot change the laws of physics.

    Gravity of a black hole is sufficient to over power the vacuum energy, and make space and time degenerate at the event horizon. The familiar laws of nature are not enforced at the event horizon. Especially the electromagnetic laws are not enforced at all, because there is no remaining energy in the partitions of electromagnetic potential. The laws of gravity are modified to conserve total energy. Gravity parameter G increases to compensate for the loss of electromagnetic potential.

    A correct view of cosmology and quantum mechanics shows that gravity fields and electromagnetic fields compete with each other for a portion of the vacuum energy potential. When the completion is evenly matched, energy is equally partitioned and space is flat.

    When gravity prevails, the electromagnetic partition is deficient, and masses attract each other through curved space. In other places. an excess of electromagnetic energy weakens gravity and curves space backward, pushing galaxies apart. That's what causes galaxies to accelerate.

    This view of science has been available since 1920. It leads to the design of engines for star ships, that also travel in time, machines that change the energy industry complete, and the risk of total destruction for the whole Earth in a single accident. For some reason it isn't taught in universities. It can be found in old books of original writings from pioneers in science.

    From universities we get a science of how to write bits of data, zeros and ones on an imaginary surface.

    When the reader realizes how enormous the advance of technology is, and how huge the risks are associated with it, then it becomes more apparent how skillfully Verlinde chooses his path forward in advancing the science.

    I'm not sure Verlinde needed to postulate a holographic universe, though the principle is useful in the derivations. Peter Lyndes noted (http://philsci-archive.pitt.edu/archive/00001197/) several years ago, arguing from Zeno's Paradoxes, that infinite precision is not possible in our universe. This is quite apart from concepts of quantum indeterminacy. Thus there is limited information available in any space-time volume. Perhaps this makes Verlinde's use of holographic screens more out of utility than need, and Verlinde is arguing a bit less heuristically.

    See

    http://arxiv.org/abs/0911.3836

    Limits to measurement in experiments governed by algorithms

    Authors: E. J. Beggs, J. F. Costa, J. V. Tucker
    (Submitted on 19 Nov 2009)

    Abstract: We pose the following question: If a physical experiment
    were to be completely controlled by an algorithm, what effect would the
    algorithm have on the physical measurements made possible by the experiment?
    In a programme to study the nature of computation possible by
    physical systems, and by algorithms coupled with physical systems, we
    have begun to analyse (i) the algorithmic nature of experimental
    procedures, and (ii) the idea of using a physical experiment as an
    oracle to Turing Machines. To answer the question, we will extend our
    theory of experimental oracles in order to use Turing machines to model
    the experimental procedures that govern the conduct of physical
    experiments. First, we specify an experiment that measures mass via
    collisions in Newtonian Dynamics; we examine its properties in
    preparation for its use as an oracle. We start to classify the
    computational power of polynomial time Turing machines with this
    experimental oracle using non-uniform complexity classes. Second, we
    show that modelling an experimenter and experimental procedure
    algorithmically imposes a limit on what can be measured with equipment.
    Indeed, the theorems suggest a new form of uncertainty principle for our
    knowledge of physical quantities measured in simple physical
    experiments. We argue that the results established here are
    representative of a huge class of experiments.

    Very interesting! The authors say with considerable eloquence at the end ....

    " ... It leads us believe that measurability in Physics is subject to laws which are the effects of the limits of computability and computational complexity. Our algorithmic model of experiments imposes limitations on the physics we used to describe it. Not all masses can be known, not because of the limitations in measurements due to experimental errors, but because of essentially internal logical limitations of the theory. The mathematics of computation theory does not allow the reading of bits of physical quantities beyond a certain limit. Quantities cannot be measured with infinite precision,
    not because of the limitations of the physical apparatus but, more deeply, because of computational reasons."

    Reply to Rob:

    Uncertainty of measurements and the interference caused by making the measurement is one of the great frustrations in science of our times. The natural way to deal with it is to average the results and come to something of a classical law from a combination of unruly events. Roger Penrose debated Henry Hawking on this topic with a claim that the generating operator of the classical law must reside with the probability function of the quantum descriptor.

    A great importance is placed on emergent properties from fundamental actions in quantum mechanics. This is the topic on which I differ the most from the main stream. If a classical law has been discovered by averaging some results, then it is much simpler to express the random generator as a probability distribution centered on the classical law. The main stream prefers to ignore all of the known classical laws and guess at a fundamental structure in quantum mechanics or a super symmetry group in quantum cosmology, and try to generate the classical laws without using any previous knowledge of them. Verlinde is involved in that work, as are most of the university research groups. Hundreds of attempts have been published .

    I prefer to look at the classical laws and guess at what fundamental principles might generate them and link them together. If you look at the progression from Copernicus to Galileo, to Tyco Brae, to Kepler, to Newton., to Poincare, to Einstein all of the progress was from opportunities of the moment discovering a new classical law by reasonable extension of the existing science.

    When we look at anything in the physical world, what we see is an average tendency and some sort of probability distribution centered on it. That’s how nature deals with uncertainties. Our brains use the same method to deal with quantum wave functions in decision making.

    Science has reached the limit of measurement on small scale objects. Several times science has reached a limit, only to discover a new technology that removes the previous limit.

    For sixty years computers have been making accurate calculations with imperfect equipment. The well known remedy is to average the results from a number of clock cycles, maybe 20 or 30 cycles, or until the average stops changing.

    In recent times there is acceptance for the science of entangled wave functions, giving the possibility of greater accuracy from fewer observations and fewer calculations. To make a prediction for the ultimate limit of small scale measurement or micro computation is interesting, but not really convincing.

    An accurate prediction would require us to know everything about the micro world, including the zero point, vacuum structure, space and time, as well as the physical significance of strings and nodes, and the contents of all the hidden dimensions. Without that knowledge, it is possible to make an estimate of the next limit and the next steps in removing it, but not the final destination of measurement science.

    One step in the future progression is to make use of dilation in time and space with measurements at high speed approaching light speed. It has been suggested that hidden dimensions will open up to become visible, and small things that cannot be measured now will be measurable. To begin these things you need to have measurements and calculations in six dimensions of space time. Travel at light speed opens up a lot of new science, but probably not the ultimate science, just some new mile stones along the way.

    This weeks' issue of New Scientist contains an article: 'The entropy force: a new direction for gravity' by Martijn van Calmthout, the same journalist who did the Volkskrant article.

    Please see: http://bit.ly/4Z8cqe

    Cheers!

    The funny thing is, I read almost exactly the same speculation by a student in a Swedish blog some years ago, 2008. The blog's name is Nymodernism, but the pages doesn't seem to be there anymore: http://nymodernism.blogsome.com

    More about the blog Nymodernism. The owner have noticed Erik Verlindes hypothese and make comments here (in fairly good google translation from Swedish to English):

    http://translate.google.com/translate?js=y&prev=_t&hl=sv&ie=UTF-8&layout...

    The article from 2007/08 about inertia, mass and gravitation as thermodynamic phenomenon is here, also in google translation:

    http://translate.google.com/translate?js=y&prev=_t&hl=sv&ie=UTF-8&layout...

    Hmm @Supun this is quite interesting! Of course, it's the holographic theory of the universe that makes the equations work (or at least some of them), but in a way, it's interesting to see how many people have actually be thinking along similar lines...

    As a matter of fact, the uncle of my significant other, had a theory linking information to entropy some two decades ago, and showed how the progression between two states, measuring the quantity of information and the quantity of entropy, would define, locally, the arrow of time; and universally, it would describe an expanding universe. He seemed also to be able to derive something akin to "electromagnetic inertia" out of his theory; how much of all that was pure imagination without any solid background, I have absolutely no idea; hee also never published anything, and, to be honest, I doubt that he would. But the point that he made was that you can start from the information/entropy pair and have everything else derived from it. This seems to be what this Swedish student has also considered. He seems to establish very well things like time and gravity (and inertia) emerging from a theory that assumes nothing beyond entropic states.

    In a sense, it's more exciting to see that many people are reasoning along the same lines and have similar ideas. Ultimately this might lead to a new foundation for science in the 21th century: we had "abstract forces" with Newton, the aether to transmit those forces in the early 19th century, particles in the 20th, and back to "abstract forces" in the 21st century...

    @ Luís Miguel Sequeira: Yes, interesting :-) The student seems to be studying history of science and not physics, but is creative and have some clue about scientific reasoning.

    I find this paragraphs most striking, where he at lenght explain the "twin paradox" as a thermodynamic phenomena (I try to make a better translation than Google):

    "The kinetic energy used to accelerate a body is, of thermodynamic reasons, not equivalent transferred to the body; the kinetic energy is also converted to other forms of energy. Some of this energy can turn to, say, friction, and leave the body as radiation, while the remaining energy stay in the body, such as various kinds of potential energy. In other words, it is not inertia that causes the energy to be consumed when a space shuttle launch its engines to accelerate, but the contrary: the conversion of kinetic energy to other forms of energy causes the experience of inertia.

    Hence one can possibly make a neat and understandable set of mass, inertia and energy. In addition, it may suggest a link with quantum mechanical phenomena. /.../

    Take the so-called twin paradox (which now is not a paradox, but it is popularly known as this). We have two identical clocks. One of them we send out on a journey in the universe near the speed of light, which can only be achieved through acceleration and deceleration - phenomena which are equivalent. When it comes back home again, the two clocks are not showing the same time. The clock from the long-distance journey has not aged as much as the one at home.

    One can correctly say that the clock from the journey exist at a higher energy level than the other; its entropy is simply lower. This because of my proposal, that energy have been added from the acceleration. It is obviously also a question about potential energy. When you carry (or "accelerate") a rock to a mountain top it will be 'loaded' with potential energy, which is then released back into kinetic energy when it falls down again. The clock here has been subject to acceleration and entered, or rather been detained at, a higher energy level, unlike the other clock, which only has 'fallen'."

    I have not studying Verlinde's essay in detail, but do he explain the time dilation in the same way?

    For the true enthusiast - a fun little interview (in Dutch) with Erik Verlinde, at Roeterseiland:

    http://www.wetenschap24.nl/video/bekijk/wmv/1/nu!-nederlander-bedenkt-revolutionaire-zwaartekrachttheorie.htm

    I do like the glass globe with ones and zero's printed on the surface...

    After reading Verlindes article I was quite fascinated. And so I'd like to bring up two points.

    1. It made me wonder if we can treat each particle as a mini black hole. It seems that black holes already follow a holographic principle of such. They store all their information on the event horizon (2D) and we clearly live in a 3D world. Black holes have elementary particles like mass, radius, spin, and not much more. Couldn't black holes be nothing more than a giant model of what an atom actually looks like. I've also read that all matter has an associated Schwartzchild Radius with it including protons, electrons, and neutrons. These radius' are actually inside the protons, otherwise, light would not be able to scatter off of atoms. It's only after the matter collapses (overcomes degeneracy pressures) that the black hole that was always there seems to be "revealed." It seems that treating particles as mini black holes would also be consistent with Verlinde's way of thinking. If atoms are black holes then all their information is stored on a 2D map and particles are somehow holographic projections of that data. And if matter is really a holographic projection of the hidden black hole and information that lies inside it and in a way then that may be where the universe ultimately stores its information. I've also read that string theory sort of evolved b/c we used to treat particles like 0-dimensional points and it resulted in many infinities when we try to merge QM and GR. String theory was invented to overcome this. Rather than treating particles like 0-dimensional points, they treated them like 1-D string loops, or tiny circles at Planck sizes. This later evolved into treating them like 2-D strings, M-strings, etc. all the way up to the 10-12 dimensions they've tossed around. Was wondering if many of these problems would be solved by treating particles like black holes and modeling them that way instead of strings. Perhaps all the information stored on the individual Schartzchild Radius', who knows.

    And my second point....

    2. After reading the paper it didn't make sense till I read what the Unruh effect is. I never heard of it before, in fact, it to me was more impressive than Verlinde's paper!!!! I'll summarize what wikipedia says "It is the prediction that an accelerating observer will observe black-body radiation where an inertial observer would observe none. In other words, the background appears to be warm from an accelerating reference frame; in layman's terms, a thermometer waved around in empty space will record a non-zero temperature." If the Unruh effect is true it basically means there HAS to be relationship between entropy and gravity and makes me wonder why Unruh didn't connect the dots. I mean entropy and temperature seem to be intimately interconnected and gravity and accelerating reference frames are essentially one in the same ala Einstein. So if accelerating reference frames, ie artificial gravity, can induce a temperature from nothingness, than assuming the converse to be true you get, that temperature can induce an artificial gravity or accelerating reference frame. I wouldn't say its circular logic necessarily, but maybe it is. There also seemed to be some discrpencies on wikipedia as to whether or not the Unruh Effect is even real. Some scientist say that it doesn't even exist and some say it does, so it seems we need a consensus that such an effect is real before we can even began to suggest Verlinde is correct since he uses the effect as the basis for his paper.

    I'll look for your comments, try not to tear me apart to badly as I'm new on this forum and this is my first post. Thanks.

    I thought the whole theory of thermodynamics is based on the kinetic theory of microscopic matter and therefore is ultimately dependant on Newtonian mechanics.
    Newtonian mechanics is everything to do with acceleration and inertia and nothing to do with gravity(Newtonian Gravity is another subject). There is no viable explanation on the origin of inertia or gravity to date.
    Literally, Newton had no idea of what gravity is, Einstein came close to explain the mechanism behind gravity but is still incomplete. They gave us working equations for inertia and gravity and that is all.

    Space is the playing field for all matter, like Einstein said, matter loves to distort space
    or warp space and in that process create gravity. But what he did not explain is how it is done. Like we all believe now, this is a very elegant idea indeed, which is backed by many experimental verifications. Einstein never set up boundaries for his equations and never liked the idea of using his equations to explain infinities. But alas, others used his equations to calculate the extremes of gravity behavior in space like black holes and singularities as if the equations were valid under those conditions and did not breakdown.
    This belief (existing only in equations with no connection to physical reality) has spawned a vast scientific theoretical industry which is speculating on many fronts even today, all without observational experimental proof on like black holes and hence on holographic and entropic principles too.

    Like Einstein said matter curves space and space tells matter on how to behave in space.
    This is all fine, but did it occur to anyone that in addition, space by itself can be naturally curved without matter being around? Therefore that a test particle will follow the natural space curves and appear to feel a fictitious force without real matter being present?
    This is the idea I put forward to explain dark matter at my website cosmicdarkmatter dot com (5th tab) published free. I also have an article to explain the origin of inertia and gravity(6th tab) for purchase.

    Tissa,

    You really ought to study the paper in depth, before offering a comment - please have a *careful* read at http://arxiv.org/pdf/1001.0785v1 and have a look at Erik Verlinde's notes at http://staff.science.uva.nl/~erikv/page20/page18/page18.html

    Thermodynamics is NOT dependent on Newtonian mechanics. In statistical mechanics it is sufficient to define a system that has a number of states, and a probability distribution of these microscopic states. No assumptions are needed about the number of spatial dimensions, or about inertia and certainly not about gravity or any other force. If you are interested in the evolution of such a system, the variable time is all you need. Please look up the definition of a canonical ensemble, if you don't believe me.

    Physicists like Bekenstein, Hawking, 't Hooft, Susskind and many others have arrived at the notion of the holographic principle after a careful analysis of what happens (according to general relativity) when a black hole is formed, and how that relates to thermodynamics. As you can read in the paper above, it IS possible to derive inertia as well as Newton's laws and the Einstein equation from the very elementary notion of holography.

    It would be very pleasant if people would actually offer relevant comments to the subject of this blog, instead of offering a variety of homegrown 'theories'....

    Cheers!

    Amateur Astronomer

    I read Verlinde's paper and both of his blogs describing it and found it interesting, but with some unanswered questions about what it is intended to become in the next version of physical science. Also I read Tissa's theories before giving an opinion about them. I have a policy of reading everyone’s writing and listening to everyone’s opinion, but applying a rather strict scientific principle in the evaluation.

    Holographic Universe theory is an effort to eliminate action at a distance from physical theories, without constructing an abstract mathematical space curvature of the Einstein type. Verlinde has used it in a somewhat different way to develop physical laws from fundamental principles. Tissa has not provided a way to eliminate action at a distance from her theories, although there are some beginnings in that direction. She has constructed something like a Kaluza-Klein theory where time is not a planar dimension, and something like a Reissner–Nordström metric where the electric field is replaced by a second gravity term. Singularities are prevented by a Planck scale maneuver, but without the usual formalism of tensor calculus. The work is interesting but probably not on the leading edge of holographic theory.

    Albert Einstein expressed his theories in terms of geometrical space curvature, because that was the only choice he had in 1916. He never clearly stated what space was constructed from that supported a geometrical curvature, although he did in a speech acknowledge that the space should have some physical structure to absorb the stress energy and resist the resulting displacement.

    Some years later the properties of space were measured, and quantum mechanics advanced far enough to describe the physical structure of space. A great difficulty occurred and is still continuing because the quantum theories require a very large energy field to reside in space, if for no other reasons than to resist curvature and to restore space to flat condition when the stress energy is removed.

    General relativity has been interpreted by many scientists to mean that the energy fields in space must be very small because of the nearly flat space that is observed almost everywhere. Already the Reissner–Nordström metric had resolved that issue in 1918, but half of the scientific community has chosen to reject the Reissner–Nordström metric and continue the dispute for 90 years.

    It is a dangerous topic for science, with far reaching military consequences that were not missed by Kaiser William, Adolph Hitler, and dozen or more other heroic leaders. Then the world was saved from destruction and a lid was put on the risky new science. It was dropped from college text books. The lid came off in 1993 with proof of entangled wave functions in Geneva. Now the world is at risk again that control of time and space might fall into the wrong hands.

    Holographic Universe theory approaches an untouchable topic that relates to the power of creation, who controls it, and what will happen if it ever gets loose. Unfortunately physical science is stuck in a rut of very slow and tedious advancement in abstract mathematics to avoid the road block of vacuum energy and the trench warfare of the great dispute. A large part of the scientific community is in favor of putting the lid back on and burning the books. The other scientists are sponsoring reprints.

    In this context Verlinde has carefully structured his advancement over the top, and meticulously left out as many troublesome things as possible. He made other things vague when ever he could, giving a very simple result from the least possible input. All of this is coming to us from the birth place of free speech.

    Verlinde’s hologram is missing some key parts. He described it as a static view in a brief moment of time. Then he doesn’t have to say exactly what it contains, how the information was transferred, or how fast it moves. As a static view, what it really says is that space has a structure and a set of physical properties that transfer information and energy from a cause to a distant action. The information can be found written on any surface that might be constructed between the cause and the action.

    This is the same thing that Isaac Newton predicted, except in Newton’s time the scientific principles had not been discovered about how to make the physical representation.

    Amateur Astronomer


    Verlinde is well established in string theory and quantum cosmology. Quite a bit of progress is being made in those areas that are expected to eventually merge into a unified theory. The biggest hindrance to completion is the lack of consensus on the physical structure of the vacuum and a way to introduce the vacuum into the unified model.



    From reading many papers, I would guess that the physics community is within a few years of completing the unification. It doesn't happen automatically. Someone has to nudge the activities in a beneficial direction.



    From that perspective Verlinde's publications and speeches on Holographic Universe are a nudge in the right direction, and a reasonable extension of his previous work. It's more like a stepping stone than a final destination.

    Johannes Koelman
    "I would guess that the physics community is within a few years of completing the unification"
    I like that positive thought!
    "It's more like a stepping stone than a final destination"
    That - in my opinion - perfectly summarizes Verlinde's contribution.
    Amateur Astronomer

    The strength of vacuum energy can be derived from general relativity without reference to quantum mechanics. It can be set equal to the potential energy density at the edge of a black hole to get an answer that will not deviate by more than a factor of 2 from any of the predictions in quantum mechanics.

    Johannes has allowed us to differ by a factor of 2 on his page. So the method is allowed at this point as an independent confirmation.

    Quantum mechanics is needed to say how the energy is structured and partitioned, not how much total energy is there.

    In Holographic Universe theory the hologram is another way to present the same information.

    Amateur Astronomer

    By partitioning the vacuum, Verlinde has established a bench mark that will be difficult for other writers to match.

    Without saying how all of the partitions are filled, he has created the confidence that there is some distribution that will correctly describe a physical situation.

    The equal partition was used in construction of Newtonian gravity, which is another way of saying space that is very nearly flat.

    Dear Johannes,

    One of the most intriguing comments made by Verlinde in his paper is that "gravity and space must be emergent; it HAS to work like this". The assumption that gravity is induced by an entropic force leads to some interesting results when one studies the dimensions in more detail and tries to keep G out as a fundamental constant. Unfortunately I couldn't find a way to get the HTML tags properly working in my response, so the layout will look a bit ugly.

    Here we go:
    F = G M/r M/r (no further explanation needed)

    In entropic terms:
    F = dS T / dx (work A=dS T delivered by force F over distance x)

    Now back to as many fundamental constants as possible (k = Boltzmann, h = 'normal' Planck, c = speed of light). Note that I actually only need to introduce Temperature (in K=Kelvin) as a variable.

    Mass (M) goes first:
    M = dS T / c^2 => k T/c^2

    Distance (m) goes next:
    m = c h / (k T)

    Then the entropic force:
    F = (k^2 T^2) / (c h)

    And then G can be derived:
    G = (h c^5) / (k^2 T^2) = c h c^2/(k T) c^2/(k T)

    Then take: F=m a:

    F = (k^2 T^2) / (c h)

    M = (k T) / c^2

    So, to my surprise:
    a = (k c T) / h = Unruh (!) (just use h/2pi to obtain h-bar)

    That''s encouraging, since the Unruh formula was derived from Black Hole physics and by just making an entropic assumption about gravity, it leads to the same formula. If this dimensional analysis is correct, there are some further implications that even go much deeper:

    Mass = M = k T / c^2 (mass is positively correlated with Temperature. This is an already proven fact)

    Distance = m = (c h) / (k T) (distance is inversely correlated with Temperature. I.e the distance was zero at the hot big bang but did become infinitely long in a black hole when its temperature approaches zero. So, there is max length to the black hole "tentacle").

    Time = s = h / (k T) (time is inversely correlated with Temperature. This implies that time went super fast during the first stages of moving energy after the hot big bang and time also becomes infinitely slow in a black hole when temperature approaches zero and no energy in it can 'move').

    Since temperature and accelleration have been already connected via the (although not yet proven) Unruh formula, one could ask the question whether the ART (with its non-inertial frames) and Verlinde's entropic approach, could both lead to a dual explanation of a locally curved space-time. With of course one important difference and that is that local temperature differences in space-time, do potentially have a stronger physical grounding (e.g. average energy on the move), than the ART, that predominantly leans on the thought construct of accelerated observers (and of course its supporting mathematical framework).

    Johannes Koelman
    Hi Agno -- not sure if I follow your derivation. What exactly do you try to accomplish? And what is ART? (From the context it seems you mean General Relativity?)
    Hi Johannes,

    I've clearly leaped too many steps forward without properly explaining what I was trying to accomplish. My apologies for that.

    The (heuristic) approach I've followed for my dimensional analysis is as follows:

    1. Assuming that gravity originates from an entropic force and using Verlinde's equation F =dS T / dx and Newton's F = G M.M/r^2, I attempted to find a way to fully express G in fundamental constants (k, c, h). Obviously this can't be achieved given the dimensions of the available constants (and someone having killed G a long time ago...). Why the constants? Because I deeply believe these create the connection between macro and micro level physics.

    2. I then tried to inject fundamental constants into elements of the Newton Gravitation law and checked that it matched the dimensions (in kg, m, s) in the entire formula F=G M.M/r^2. I've assumed k = m^2 kg/ (s^2 K), h = m^2 kg / s, c = m/s.

    3. So, I started with mass and described it entropically as dS T / c^2. Entropy (S) always comes with a 'k' (since the Omega in k ln(Omega) is dimensionless), this gives you k T / c^2. Checked the dimension, and indeed kg comes out as it should.

    4. Then it's just a matter of squeezing all fundamental constants into the dimensional straight jacket of Newton's law, i.e. r = m, G = m^3/ (kg s^2) and F = kg.m /s^2 (Newton). And I found that it only worked when I kept T in. The dimension of Boltzman's k is m^2 kg/ (s^2 K) and once this gets introduced (and entropic forces can't escape the k), you need to keep the T (in Kelvin) in and mix match it with the constants.

    5. Since to my surprise this line of reasoning exactly reproduced the Unruh formula relating a to T, I felt that I was on the right track. In hindsight I could of course also have started from the Unruh formula and calculating it back towards the mass (M). It doesn't really matter, but it does imply that if we assume Unruh to be true, gravity MUST have an entropic source. It can't be any other way.

    6. I then tried to understand what the physical meaning of G, F and r could be when expressed in fundamental constants and T. And also checked that the resulting dependency on T (of distance, G , F and also time) made sense for f.i. extreme cases like the Big Bang starting point and for a Black Hole.

    6. The most stunning outcome is that this reasoning leads to time (s) and distance (m) being temperature dependent, hence my (provoking) statement that it might be the Temperature of a mass that curves space-time...

    ART is indeed a Dutch acronym for GR.

    Cheers.

    Agno

    Johannes,

    There are several reasons why I consider Verlinde's approach highly questionable:

    1) Gravity does not need to be "derived" from something more fundamental. General Relativity has shown that gravitational field naturally follows from gauge invariance, that is, from demanding that physics stays invariant to transformations relating frames of reference in accelerated motion. In this context, attempting to derive classical gravity from some other underlying foundation is simply unmotivated.

    2) Classical gravitation arises exclusively in a deterministic context, as completely specified by the space-time metric, whereas entropy is a probabilistic concept that require a statistical description of phenomena.

    3) Unruh temperature is an example of a relativistic EFFECT induced by gravitation and is incorrect to be interpreted the other way around, as a physical CAUSE of gravitation. One must also recall that observational evidence for the Unruh effect and Unruh radiation remains controversial as of today. Same goes for the holographic principle.

    4) Gravitational attraction exists even when there is no change in position involved. A typical example is a static perfect fluid immersed in a centrally symmetric gravitational field. In this case the pressure gradient of the fluid balances the gravitational force and the fluid remains at rest. Consider now the assertion:

    "Entropic acceleration results from the tendency of a system to evolve such that there is an increase in the minimum number of bits required to describe the system in all its details. Could it be that gravitational attraction results from nothing more than a growth in number of bits required? Verlinde argues that such is indeed the case"

    This fails to be true in the example above since there is no change of position in time and an increase in the "number of bits" is simply unmotivated.

    Regards,

    Ervin Goldfain

    Johannes Koelman
    Hi Ervin -- let  me try to address briefly each of the points you raise:

    1) Whether there is a need to derive gravity from something more fundamental, is an open question. When we have a fully consistent theory of quantum-gravity we will probably know.

    2) True.

    3) Can you explain why reversing the logic behind the Unruh effect would be invalid?
    I agree that both the Unruh effect and the holographic principle yield consistent descriptions of gravity, but have yet to be validated by observations.

    4) A microscopic (thermal) change in position is all that is needed.
    The gravitational acceleration from entropy is no different than the entropic force observed for polymers. The force (or acceleration) is proportional to the gradient in the logarithm of the number of states and also proportional to the temperature. The temperature is needed for the microscopic degrees of freedom to sample the state space around the current configuration and to 'feel' the gradient.

    Regards,
    Johannes
    "Can you explain why reversing the logic behind the Unruh effect would be invalid?"

    An increase in temperature (say from a nearby black-body source) can be detected in a fixed frame of reference where there is no acceleration. By contrast, Unruh effect requires an accelerated frame of reference to become perceivable.
    In short, I fail to see the rationale for reversing the logic and attempting to derive gravity from one of its physical consequences. It is like saying that the red-shift in a gravitational field is the actual cause of that field.

    "A microscopic (thermal) change in position is all that is needed.
    The gravitational acceleration from entropy is no different than the entropic force observed for polymers. The force (or acceleration) is proportional to the gradient in the logarithm of the number of states and also proportional to the temperature. The temperature is needed for the microscopic degrees of freedom to sample the state space around the current configuration and to 'feel' the gradient."

    Ideal fluids in General Relativity are described macroscopically through pressure and energy density, which are related through their equation of state. For a simple fluid in thermal equilibrium, the pressure can always be expressed as a function of energy density and its specific entropy. You are talking about a microscopically based description of the fluid to make connection to the alleged entropic nature of gravity, but I don't see the real need for such a description. Such a description is not going to modify what is already known, that is, the equation of motion for the fluid.

    Regards,

    Ervin

    Johannes Koelman
    Ervin -- whilst you, and all the skeptics towards Verlinde's hypothesis, might be right (time will tell), it strikes me that you are trying to enforce a conservative approach that might stall progress. As long as new perspectives open and no inconsistencies arise, I am willing to follow Verlinde in his arguments.

    I see a similarity to atomists at the end of the 19th century postulating that there is a hidden atomistic reality behind the continuum description of fluids, whilst continuum-description supporters argue that the Navier-Stokes equations contain all te physics needed to describe fluid dynamics.

    Time will tell if a 'holographic atomistic' description of gravity is the right step. 
    Johannes,

    You say:

    "I see a similarity to atomists at the end of the 19th century postulating that there is a hidden atomistic reality behind the continuum description of fluids, whilst continuum-description supporters argue that the Navier-Stokes equations contain all the physics needed to describe fluid dynamics"

    I find your characterization inaccurate. Reality is that I am not opposed AT ALL to new avenues along this line of research. To prove my point, here are three links to papers that I published in nonlinear dynamics journals. They connect gravity to fractal dimensionality of space-time beyond the Standard Model of particle physics:

    http://dx.doi.org/10.1016/j.chaos.2005.09.012
    http://dx.doi.org/10.1016/j.chaos.2003.08.014
    http://dx.doi.org/10.1016/j.cnsns.2006.06.001

    Regards,

    Ervin Goldfain

    Hi Ervin,

    You did raise some very good concerns earlier on in this thread (and in the dark enery blog as well). Some of these I can agree with... BUT I would suggest that it is useful to see this new proposal by Verlinde (and the preceding work by Jacobson, Padmanabhan and also Susskind, 't Hooft and Maldacena) in the proper context.

    Since the late 70's there has been an intense struggle to - somehow - forge unification between quantum field theory (QED and quantumchromodynamics) and general relativity. At that time the overriding impression was that 'unification was just around the corner' as concepts from Yang-Mills theory and QCD were extended to what was later to become string theory. It seemed this would work exceedingly well, and certainly the Electroweak and strong interactions are now part of a unified framework, even if one only takes the standard model SU(3) x SU(2) x SU(1) gauge fields into consideration.

    However... integrating general relativity into string theory (or into canonical quantum gravity) has turned out to be somewhat like "hammering a square peg into a round hole" - it can be made to fit, just maybe (!), at the cost of large numbers of additional compact dimensions, strange spin 2 gravitons or other constructs...

    Now, the ideas originated by John Wheeler ("it from bit", as suggested also by Stephen Wolfram, Sakharov and many others) and holography may offer a way out of this 40-year long conumdrum. As Verlinde shows a case can be made that the effects we see as gravitation may be emergent, not fundamental at all, and amenable to description by statistical mechanics. WHETHER this works out, still has to be seen obviously...

    But if it would work, it might lighten the load on string theory and on other unified field theories immensely - they might be limited to the *actual* gauge fields, and macroscopic behaviour including what we used to call gravitation could be derived using stochastic methods.

    All this would of course not mean that 'general relativity is wrong' - GR will remain probably the most impressive intellectual achievement by a single person ever. But a holographic theory might be more amenable to integration with other very succesful constructs...

    More later,
    Best Regards!

    Hello Bob,

    The reason for my skepticism is that there are simply TOO MANY “if’s” for the holographic/entropic theory to work as a successful unification framework. To meet such a grandiose claim, not only that the theory must consistently blend into GR at low-energy scales, but it must also be able to unveil both the physics of the dark sector along with the Standard Model of HEP. This is a formidable task, make no mistake about it: to be credible, the theory must be able to explain all the currently open questions of SM (the origin of electroweak unification, the family replication problem, the origin of chiral symmetry breaking, the gauge hierarchy problem, the anomalous magnetic moment of leptons, the mechanism of hadronization in the infrared QCD and so on).

    Maybe it’s me but I have serious doubts that the holographic/entropic theory of gravity is on the right track.

    Regards,

    Ervin Goldfain

    Hi Ervin,

    Thank you for your reply - however, I must have been unclear and/or obtuse in my earlier post.

    It is my distinct impression that Verlinde's proposal is NOT a unification framework, and certainly not the basis for a 'grand unified theory' or anything of the sort. Again, please refer to the paper itself :)

    Rather, it might be an alternative description of gravitational phenomena which states that gravity DOES NOT EXIST (...as a fundamental force). Hence it would make no sense to 'unify' it at high energies with the three SM forces.

    Intuitively I have great problems with this picture of nature without gravitation as one of the fundamental forces - but of course that is just a habit of thought. Gravity has always provided the archetype of the concept of 'force' as far back as the days of Kepler. Now it may be that the the ideas of 'force' and 'field' persist (in the modified meaning of gauge field theories), while gravitation might be a stochastic epi-phenomenon.

    Of course it would mean that, in the specific physical situations where we used to hope for 'unification' (in those rare cases where both QFT and gravitation are important), we will now have to rely on another formalism (holography and the equipartition theorem and ...) to provide us with answers.

    I do agree that the idea still relies on some handwaving, many IF's and a somewhat intuitive picture. The paper reports on the fact that even with only a heuristic approach remarkable results can be obtained - emergent inertia and gravitation, as well as several hints about emergent spatial dimensions.

    And yes - it needs lots of work, especially on the foundational questions. Will it work? We'll only know by exploring further. :)

    Regards!
    Bob

    Hi Bob,

    Thanks for your reply.

    Since classical gravity follows from gauge invariance, one needs to show that, not only gravity, but the ENTIRE GAUGE GROUP of particle physics represents an emerging property from an underlying theory. To do that, one needs to accept the idea that dynamics on high energy scales is NO LONGER in equilibrium. One major implication of this ansatz is the transformation of continuum space-time into a fractal structure. I published a number of papers that show how gravity and the gauge interactions of the Standard Model are naturally unified using this approach.

    Here is the link for two of these articles:

    http://dx.doi.org/10.1016/j.cnsns.2006.06.001

    http://dx.doi.org/10.1016/j.cnsns.2006.12.007

    Regards,

    Ervin Goldfain

    Hi Ervin,

    Hmmm... interesting! I think this is where you and I differ in opinion:

    No, NOT the entire gauge group of particle physics needs to be derived. It might be sufficient if gravitational phenomena can be explained from holography and entropy.

    Gravitation is than truly the 'odd man out' - it would be an ensemble theory on the level of Boltzmann's statistical mechanics, and the state space might be provided by the available configurations of bits on the screens.

    For the other interactions the current SU(3) x SU(2) X SU(1) model suffices very well - or a much more unified view (without gravitation...) in string theory.

    I will have a careful look at your papers later - I am out of time. At first sight it reminds me a bit of Renate Loll's work at Utrecht University - admittedly I've never had a taste for constructive geometry because the selection of a base geometry (spinors for Roger Penrose, triangulations with Loll) seems relatively arbitrary. But I'll have a read first!!

    Take care & Best regards,
    Bob

    Hello Ervin,

    I can only retrieve abstracts from Communications in Nonlinear Science and Numerical Simulation and Chaos, Solitons & Fractals. I don't have those Elsevier titles available, unless I go get them from the nearest university library... Downloading requires a USD 31.50 charge each.

    If you might have a suitable preprint on Arxiv (or elsewhere), it would be nice.

    Best Regards,
    Bob

    Hello Bob,

    I can forward you the preprints if you give me your e-mail address. My e-mail is:

    ervingoldfain@gmail.com

    Regards,

    Ervin

    Ervin,

    "1) Gravity does not need to be "derived" from something more fundamental. General Relativity has shown that gravitational field naturally follows from gauge invariance, that is, from demanding that physics stays invariant to transformations relating frames of reference in accelerated motion. In this context, attempting to derive classical gravity from some other underlying foundation is simply unmotivated."

    I can only se that this statement is highly unmotivated. The problem Verlinde try to solve, is the connection between general relativity and quantum physics. It is perhaps this way, that gravity _need_ to be derived from something more fundamental, to solve the puzzle.

    Charles,

    As far as we know today, deriving General Relativity from Quantum Gravity (QG) remains problematic for many reasons. Let us assume that QG becomes relevant at very high energies, somewhere below or near the Planck scale. There is no basis to assume that the concept of entropy, as described by equilibrium statistical physics and Boltzmann-Gibbs theory at our energy scale, remains a sound concept near the Planck region, where far from equilibrium dynamics is likely to develop. Therefore I don't see how using entropy solves the connection between QG and General Relativity.

    Regards,

    Ervin Goldfain

    Amateur Astronomer

    I tend to agree with Johannes on this one.

    If it wasn't important a dozen top people in different countries would not be competing for small advantages in the derivation.

    First a word about entropy: The use Verlinde makes of Entropy and Temperature is a convenient device, but not the only way to describe the physical system. Convenience in this case means that Entropy allows progress without a major confrontation about properties of the vacuum and how they link to observable fields.

    Next some words about metrics and gage invariance in transformations: These must be regarded as a simplified and abstract technique of describing physical things approximately to give an answer that is temporarily acceptable. If they are to be generalized in a permanently significant science that can be extended into new areas of research, then they must be completely reconstructed from fundamental principles in which quantum mechanical effects are included in the field equations.

    The debate between Johannes and Ervin looks to me like the continuation of arguments between quantum mechanics and cosmology. There is a stalemate, and Verlinde is trying to break the stalemate.

    I would like to hear an opinion from Ervin about the structure and action of the vacuum in his metrics and how the mathematical equations are mapped into to the physical science. More clearly stated, what physical properties of the vacuum support geometrical curvature, and how do those physical properties propagate the curvature from one place to another on a microscopic scale?

    ==>Hint: You won't find the answer in a metric or a gauge or a invariant transformation.

    ==> Other Hint: Entropy can describe microscopic gradients in physical systems.

    The hologram is a step toward finding answers, and unless there is a really surprising response to the question, I would say there is a motivation for holographic research.

    Third some thoughts about non moving systems: Everything is moving. Everything vibrates. Everyone should know this. Stress energy changes the frequency of vibration, the mode of vibration, and the partition of energy levels. Metrics and gauges do not account for vibrations, frequencies, modes, or partition functions.

    Failing to answer the question has delayed scientific advancement for 75 years, and diverted a lot of resources into a tedious discussion of abstract mathematics, (which I enjoy greatly)

    I suggest to the readers that there is motivation for some of us.

    Verlinde has been working on answers for most of his career.

    Amateur Astronomer

    I would argue that quantum gravity is relevant at very low energy levels, especially in low density clouds of dust or gas located a far distance from large masses of condensed matter.

    Hontas had a discussion of this topic related to her graduate research.

    Quantum gravity is important in research about critical densities for star formation, dark energy of accelerating galaxies, transparency of space, and origin of the universe.

    People who want to work in those fields are motivated to get a unified quantum cosmology, and are likely to succeed against opposition.

    Progress is fairly rapid, and the problematic areas are being identified and resolved.

    Holographic methods are a step toward resolving problems.

    Amateur Astronomer

    Eventually all of the physical laws must be emergent from the fundamental properties of the vacuum.

    That means the physical vacuum, not the metrics, not the gauges, not the coordinate transformations, but the real thing mapped into a unified theory with predictions that can be tested.

    Until that is done there is un undiscovered science of a fundamental importance and a motivation to find it.

    Science is not ready for that yet, but we will be happy to erect a monument in memory of the (short ) career of any scientist who makes the attempt.

    Verlinde is not ready for a monument yet. So he chose a one small part of the problem and moved it off dead center.

    Amateur Astronomer

    Why must physical laws emerge from the vacuum?

    If you look at any physical law like gravity, electrodynamics, or inertia, the classical laws are really describing some aspect of what can be done in the vacuum and how the vacuum responds to any type of action.

    The picture is not complete now, so there are undiscovered laws that will emerge in a unified theory.

    Amateur Astronomer

    How do we know that physical laws emerge from the vacuum?

    About 50 years ago astronomers looked at distant stars and galaxies to learn about the physical laws that operate in those distant places.

    They found that physical laws are the same everywhere.

    It leads to conclusion that physical laws must emerge from the vacuum, because the vacuum is the only thing that gees everywhere and connects the distant places together.

    If one law did not emerge from the vacuum, then it might apply locally in one place, but not universally everywhere, because it has no way to propagate to distant places.

    Emergent gravity is not a surprise or a novelty. It is an expectation and a requirement for credibility of a new theory. Verlinde stressed the emergence of inertia in his web page, which is another physical law that must emerge from vacuum, and is not well presented by previous writers.

    The vacuum supports all of the physical laws in science in an unchanging way, in spite of anything we can take from the vacuum or donate to the vacuum. That means the vacuum is far more powerful than anything in our technology. So much power always represents some type of danger.

    Holograph theory is a window for taking a brief look at the vacuum, without getting sucked in. Woops, sorry for the metaphor.

    Dear Johannes Koelman, thank you very much for your insights and interpretations of Verlinde's Theory as well as all of your derivations and descriptions as they pertain to Dark Energy as well. As I believe that Verlinde is on to something as well as you and your contributions considering dark energy, I studied his papers and your writings considerably for about two weeks now before drawing some interesting conclusions and derivations of my own.

    Verlinde wants you to treat the internal energy held by a mass, m and interchange it with the information stored on a holographic screen. Although Verlinde does not consider photons, I believe that they can be modeled the same way. For instance, they are similar to ordinary mass in that they are made up of internal energy. In the above derivation, Verlinde asks you to treat a particle of mass m as nothing but a holographic sphere which stores all the internal energy of the mass as bits. By using the same philosophy on a photon I asked myself what would happen if you were to treat a photon of frequency v as nothing but a holographic sphere which stores all the internal energy of the photon’s frequency, not mass, as bits. The result was that the photon would be gravitationally attractive despite not having a mass!!

    If one considers that such a "photonic attraction" can exist and couples it with the fact that photons have been emmitted since the birth of stars and the big bang one can account for a large portion of energy and gravitational potential that exists out there in the far reaches of the universe, far away from all matter. It could easily explain what dark matter and dark energy are in the context of your derivations. If 75% of the universe is dark energy, then dark energy may be nothing more than energy of all the photons that have been emitted since the big bang (energy in photons is same energy in dark energy!) . An attractive force spontaneously emerges from photons using Verlinde's model on photons. One would need to create a model that would determine just how much energy has been emitted in the form of photons since the big bang and try to determine if the amount of energy could make up
    as much as 75% of the universe' energy. One could also look locally at a galaxy to determine if the photons emitted in the form of all EM spectrums from both stars and cooling hot bodies like planets could account for enough
    energy with a gravitational attraction to stabilize spiral galaxies from flinging apart (dark matter)

    I created a website to show my derivations with diagrams that were based on your reasoning and Verlinde's model and it shows derivations for photonic attraction as well. Please take a look at this and tell me your thoughts. I
    would love if you decided it had merit to write another article perhaps discussing this in more thorough detail with your richer background since I only have an undergraduate degree in Physics from GA Tech and certainly have
    left room for possible mistakes in the derivation. Many thanks for taking the time to read this, visit the website, and consider its merits.

    http://holographicuniverse.info/

    Amateur Astronomer

    What new science will be discovered in the unified quantum gravity?

    Johannes has given us the answer in his next article.

    http://www.scientificblogging.com/hammock_physicist/it_bit_how_get_rid_d...

    Dark energy is the obvious answer and a very big prize.

    A unified theory will provide a law that describes the dark energy.

    In any credible new theory  dark energy must emerge from the vacuum, because it operates in places where there is simply nothing else present for it to emerge from.

    Dark energy is thought to account for about 70% of all energy in the universe, but is not well understood.

    If 70% of the universe is not a justification for new research, then I would like to know what motivations are operating for decision making processes.

    I agree with Johannes on this topic. The dark energy must be detected on the hologram.

    Amateur Astronomer

    What new science will be discovered in the unified quantum gravity?

    Johannes has given us the answer in his next article.

    http://www.scientificblogging.com/hammock_physicist/it_bit_how_get_rid_d...

    Dark energy is the obvious answer and a very big prize.

    A unified theory will provide a law that describes the dark energy.

    In any credible new theory  dark energy must emerge from the vacuum, because it operates in places where there is simply nothing else present for it to emerge from.

    Dark energy is thought to account for about 70% of all energy in the universe, but is not well understood.

    If 70% of the universe is not a justification for new research, then I would like to know what motivations are operating for decision making processes.

    I agree with Johannes on this topic. The dark energy must be detected on the hologram.

    Hi Jerry what do you think about attributing this dark energy to "photonic attraction" - please see above post. I believe I have derived a photonic attraction force using Verlinde's model on a photon which suggests that photons are attractive despite not having any mass. In light of this, no pun intended, dark energy is nothing more than electromagnetic energy, or photons, that has been given off for 14 billion years. It forms the characteristic halos around our galaxies that we attribute to dark matters presence and it exists so far from radiating matter that it should account for the matter in the universe accelerating apart - it's also consistent with Koelmans mathematical derivations for dark energy as well. I've shown the derivations for "photonic attraction" using Verlinde's model at this link below if your interested in critiquing it. Many thanks, Matt

    http://holographicuniverse.info/

    Amateur Astronomer

    Matthew,

    I read your web page and believe the methods have some merit. It lacks a lot of things that Verlinde deliberately left out. Like his and other recent pages from different writers you have part of a story but not a hole story, and some concepts and principles, but not a unified model. Also it isn't relativistically invariant.

    Your page reminds me of things people were trying to write about 15 years ago, before discovery of accelerating galaxies. Since then there has been a lot of work to say why galaxies are accelerating. I didn't see accelerating galaxies in your work

    You have a mixture of classical and quantum physics of a type that can result from averaging a large number of measurements. For a single event you would need a probability function for a wave equation. Averaging is fine as long as everyone knows it is being done.

    Photons interact with each other in complicated ways such as interference patterns and scattering. With a lot of cases to choose from, the resulting interactions could be attraction or repulsion depending on the polarities, wave lengths, orientations, and phase angles.

    Your attraction calculations are one of the several possible things that can occur all at the same time in a small region of space.

    For the most part I believe that space has an excess of electromagnetic energy, but not the large excess that you suggested. Most scientists consider photons to enter into the stress energy of space and alter the curvature in general relativity. They don’t agree with each other about the size of the effect and whether or not it adds attraction or repulsion, so they probably aren’t going to agree with you either. I’m in the group that believes the photons contribute to repulsion most of the time except in special cases where the interference patterns are correctly aligned to produce an imitation of ordinary gravity ( transverse quadrupole of spin 2, Poynting vector not extinguished) in a topic called gravity induction.

    So I guess my net response is that I believe you described a physical system that can occur in a localized area, but seldom does occur in the natural universe. When it does occur the effects are small at ordinary power levels.

    There is a related discussion topic that sometime occurs about something called field effect propulsion, a new type of engine. It is a special interest of mine, but mostly shared among a small group of friends. The scientific community has not moved beyond the fundamental principles, in a dispute that began in 1918. A few words change occasionally, and people come and go from the groups, but the basic disagreement has not changed. Verlinde is offering a chance to make a change.

    In the direction your work is taking, I would guess that you will eventually be counted among the opposition who say our universe will die and there is nothing we can do about it, we can never travel to other stars and there’s not much do there anyway, unification of gravity with quantum mechanics is not worth doing unless it blows up in our faces and wipes out one side of the dispute.

    Verlinde is not saying those things, and if that was not your intention then I suggest you add something to your work that says what direction you are taking in the next steps.

    Amateur Astronomer

    The exchange between Bob and Ervin is a really good one and something I would like to see more of on this web site.

    I'm going to agree with Ervin on a few things, and that is surprising to me, considering how the discussion began.

    First the entire gage group must emerge from the vacuum, and be described by the holograms if the laws of physics are the same everywhere, because the vacuum is the only thing that goes every where. This issue was resolved in the 1960's.

    Second I looked at the papers on fractals and found some useful things described, but not necessarily the way I would have described them.

    Fractal space is an interesting mathematical concept that can be related to the clustering of zero point oscillators in the physical universe. Clustering is necessary to meet the rather strict symmetry requirements of vacuum space on the microscopic level.

    In a sense the whole discussion is about how to bridge the gap between the micro world and the macro world. From the micro side of the debate there is clustering and recursion starting from the zero point and building upward in larger structures. Fractals are the abstraction of recursive mathematics, in a clustering geometry. So there might be some common ground there, or some useful mathematical devices.

    Geometry is not my favorite way to describe space, but much of the published work is of that type and very adequate in the purposes it was produced for. As much as possible I would prefer for geometry to be replaced by physical constructions with properties that can be measured. Science has progressed far enough to make an attempt of that type.

    Third and final point for now due to time constraints, the difficulties are very large in unifying gravity with quantum mechanics , but the people who work on it are very capable. Holographic theory is one of the tools, and must develop considerably from it's present definition to have a chance of remaining on the leading edge.

    The holograms at present are static snap shots in a brief moment. To advance holography, the writers will need to define them with a formalism in real time, and decide whether or not they have rest mass, move at light speed, or are just established as a mathematical abstraction with no fundamental existence of their own.

    String theory is useful, but to reach unification, we need networks of strings connected together in 10 dimensions or more. Like the clusters and fractals, the strings must have a larger structure to merge with the other theories in the many places that are necessary.

    In either case I regard the holograms as a way of looking at the vacuum , without waging a major assault on some strongly constructed objections.

    Unification depends entirely on a rigorous physical description of the vacuum and how the physical laws emerge from it, including the complete gage group as well as the dark energy. That is why it is so hard to complete the unification.

    Thanks Bob and Ervin for the discussions and insights into the missing parts of physics.

    Hi Jerry,

    Thank you for your kind comments, and your many contributions. Some of it I don't really understand - but that must be me, since that happens to me a lot ;) I did notice you have a keen sense of some of the 'politics' and sensitivities involved. It may be that - to be heard at all - careful phrasing and a step-by-step progression are necessary.

    Which brings me to your and Ervin's comments on what might be described as the 'scope' of entropic gravity. I'm still thinking about the objections raised by Ervin, however, I'm convinced at least about the following:

    - Verlinde's (and Jacobson's) proposal currently "only" aims to offer an alternative description of gravitation, and not of the other gauge fields;
    - holography as described by Susskind and 't Hooft is pertinent to mass distributions, and not (necessarily) to quantum numbers and gauge forces;
    - reading section 6.2 of Verlinde's paper (and reading between those lines) he seems to hint towards a follow-up based on decoupled open strings (without gravity);
    - there may be hints in the fact that Verlinde considers *both* sides of the screen, and section 6.2 figure 6 hints of both open and closed string states, living on the inside/outside of that screen;
    - closed strings may not be fundamental, but dual to... open strings? open strings made out of bits?
    - there is something funny about h-bar dropping out of the equations in section 3, as he discusses halfway down page 10. It makes you wonder where exactly the effects of the microscopic description cross over into macroscopic gravitation. I would initially guess at very small scales, where the Compton wavelength is of the order of the Plank length - but that may be totally untrue and fluctuations in gravitation might be noticeable at other scales?

    There is LOTs of info hidden away in those innocuous sentences in sections 6.2...6.4

    Cheers all :)

    Amateur Astronomer
    Thanks Bob.

    I believe you are completely correct about the intent of Verlinde's papers and explanations, also about the other papers.

    Verlinde put a lot of effort into the explanation of his very limited scope in the recent articles, probably because his readers are very anxious to see advancement in this area , and would be quick to make more of it than he intended.

    I took it as a general introduction for the non specialists to some technical work he is considering maybe an extensive program of formalism, and also as a feeler to see what type of interest there might be, and who else might be interested in working in that direction.

    In reading his papers I noticed that Verlinde stressed the emergent inertia as much or more than the gravity as something he had contributed. That is important, because gravity and inertia represent about half of the long-range operators, electricity and magnetism being the other half. Other short range nuclear forces are probably emergent, but probably not visible on a typical hologram, except as an artifact of particles and radiation.

    Step by step progression is probably a good thing at this time, especially for a university professor. Other people in the past attempted a faster progression and quickly came up a against a set of assumptions in the Dirac sea of energy debate.

    It takes a lot of steps to get to unification, especially if the major part of physical science has to emerge from fundamentals, as I believe it does.

    The biggest obstacle is the debate about Dirac sea of energy. That’s why we have holographic theory, to bypass the road block in hopes that it will be resolved in the several steps that follow.

    I’m strongly in the Dirac camp, and not constrained by a professorship. Also the scientific evidence seem to be weighted about 75% in Dirac’s favor. Since the energy density of the Dirac sea can be derived from metrics of GR without reference to QM, and is essentially in agreement with Dirac’s predictions, it seem to be only a matter of time before the issue fades away.

    In your discussions with Ervin, the topics appeared to start as a continuation of the Dirac debate, but toward the end looked more like a fading of that issue and more of a collaboration on the next steps. I believe that exchange was a small glimpse of what is happening on a larger scale in the scientific community.

    If we really are going to approach a Dirac sea of energy and extract all of the physical laws from it’s fundamental principles, it is a good idea be cautious about how it is done and how the results are used. Then we are talking about many small steps and a lot of careers in science.

    Verlinde has referenced the partition function several times in his holographic discussions. Partition seems to be the only practical way to reconcile a Dirac sea with GR, and certainly would be needed if we are going to extract a whole set of physical laws from the Dirac sea. He didn’t complete the picture yet about how the reconciliation takes place, but the parts he did include are a gentle and friendly hint to the opposition that the debate is coming to an end, and it would be good to reposition their resources for the next steps.

    Science spent a lot of time trying to unite the very small with the very large. Now with holograms and fractals the trend appears to be an attempt to make the unification on an intermediate sized scale. That agrees somewhat with the way large and small things are joined in other types of activities. The large things get partitioned, and the small things get assembled into groups. So the direction looks about right, and there is a lot of work to do.

    To me the scaling factor in Johannes’ writing was a step toward unification on an intermediate scale, using a device that has been acceptable to almost everyone since the seventeenth century. There are other ways like thermodynamics to express the same concepts, but they don’t have the same history of majority consensus. In thinking of how QM relates to classical laws, the connection is always made by averaging a certain number of small things taken together as a group. Its another type of scaling.

    Thanks again for your reply.
    Amateur Astronomer

    Bob,

    the scientific community usually puts the boundary between QM and classical laws somewhere near the point at which the wavelength of an object is equal to the physical size of the object.

    That puts electrons on the borderline, photons in the QM domain, and protons in the classical range. There is a lot of overlap because of the fuzziness of probability distributions. QM invades the classical realm by chance encounters, and classical laws operate in QM territory when groups of chance happenings make some type of average.

    So the transition is a gradual one that shifts the dominant trait, but never completely extinguishes the subdominant factor.

    The result is a quantum cosmology that embraces both concepts.

    The best minds have debated the difference between chance happenings and unknown cases for events. For the most part I favor the unknown causes instead of the chance happenings, I use the terms interchangeably.

    With string theory committed to hidden dimensions, the QM arguments against hidden causes lost a lot of support.

    Unknown causes is not a very satisfactory way to write science. There is a plan to identify the causes, and it is related to the unification studies.

    For now I believe the next steps are an experimental program of scaling on both ends, macro and micro domains. Fractals are a way to introduce scaling and a recursion that tends toward coarse graining on the macro domain without arbitrary constructions or loss of information. Less well known, clustering is a way to introduce the concept or smoothing or averaging on the micro domain in a natural way that probably does happen .

    It would not be too surprising if fractals and clustering met together on a hologram or some similar intermediate scale. That seems to be the direction holograms are taking.

    I have a private joke and get a silent laugh every time I think of the criticism about scaling in Johannes’ dark energy article.

    http://www.scientificblogging.com/hammock_physicist/it_bit_how_get_rid_d...

    If scaling is not to be done on the universe and 123 orders of magnitude, then why do we have words to describe scaling, and mathematical tools to accomplish it?

    The answer is that scaling is the preferred route to unification, and the one that is actually done in nature.

    Woops! I told the secret. Now I have to find a new private joke.

    Amateur Astronomer

    Bob,

    I’m supposed to be finding a new joke, but here I am still laughing at the old one.

    Some of my favorite scaling factors are called kilogram, meter, second, and degree Kelvin.

    Most people probably think of these things as units of arbitrary choice, and that is true in a small context.

    In fact all of them are scaling factors that fill a necessary function and are chosen with good reasons.

    A question for the philosophers: Can a decision be truly arbitrary if it is necessary and sufficient for a purpose?

    For sure there are some choices. We could have millimeters and kilometers. In fact there really are such things that differ only by a string of zeros, making all of them scaling factors of different magnitudes.

    Imagine for a moment that we bought a new microwave oven, and the instructions came without scaling factors. There were two competing models with different instruction books. Model A that we like very well for the way it fits in the kitchen, looks a lot like what the neighbors are using. It has instructions given in terms of fractional parts of the universe size age and energy. We find it hard to read, and simply impossible to implement in our kitchen. Model B has some great control features and a perfect record of reliability. Instructions for it are written in multiples of natural Planck units. We cant use that one either.

    Company A and company B are at odds with each other and have tried for years to put each other out of business. The struggle consumed a lot of resources such that both companies became a little bit obsolete in their technology. Then company C came on the scene and declared that they have a new model with up to date components, and the instructions are written with familiar scaling factors, but the design is experimental and needs some improvement.

    We rush out and test the new oven and it cooks our food just fine, but the sales team doesn’t want to sell it to us because it doesn’t meet their expectations. So we send to Amsterdam and get one delivered by air mail.

    Scaling factors are such a big part of our lives that we couldn’t function without them.

    Apologies in advance.

    Now I really do have to get a new joke.

    Hi Jerry,

    thanks for your physics jokes, we could use some. :)

    And "the design is experimental and needs some imporvement" - well, isn't that what keeps people in business? It would be a sad moment when this game would be finished, and no more improvements are called for...

    Take care,
    Bob

    Amateur Astronomer
    Thanks Bob. I guess the science that is waiting to be discovered is bigger than all of the past discoveries. Also the undiscovered jokes will be better than the ones we already heard. Topics we are struggling with now are pointing toward some really big advancements, not the final discovery or the ultimate theory, just some big steps along the way. Big steps can be really disruptive, so we are looking at how to subdivide the steps into a manageable portfolio. Eventually everything gets changed by science and other factors. If you look at encyclopedias and how people looked , acted, and talked a few decades ago, or a few centuries ago, there were very big adjustments, and a lot of difficulties in making the transitions. Now the changes we are talking about are bigger than any that occurred in the past. So we need to have someway to manage the stress and mitigate the difficulties in making the adjustments. When I find myself too much engaged in the difficulties of change, then it helps to apply a scaling factor and laugh a little.
    If you were to believe the scientist on the way they describe gravity is problematic.
    The sun should have already pulled apart Mercury millions of years ago, due to the sun's sheer mass if you were to beleive the laws of gravity, the same could be said for Saturn's rings?
    The only explabnation for either not happening is opposing magnetic forces.
    The theories and laws of phyisics may work well here on earth, but in outer reaches of space, it doesn't compute
    Centrifugal force throws matter outwards so how do the scientist propose how gravity is formed.
    And for matter to be drawn in from outside it must create vortexes at its poles.
    Laws are written to protect those who wrote them and uphold them.
    It may be time for those to start thinking outside the box instead of using it to hide in, otherwise we may never find out the truth until it's too late.

    Pardon my ignorance, but would this view allow for closed-solutions to multi-body gravitational scenarios?

    I would like to advertise my project in physics here as well
    http://www.mgkanda.ru/pdf/mathsru.pdf
    It has the same idea of unified field theory.

    First came the underpinnings of time as well as of electromagnetism. A 'natural medium' having nothing to do with space, but from which space itself including matter and energy emerge and consist. Time itself gives rise to space and matter and energy therein; time is not just passive ticks of the clock nor an independant variable, but in fact that which gives rise to all else. However for thermodymics to be obeyed, space cannot be continually fed with matter and energy through continued causal changes, so gravity becomes the mechanism for excess to be absorbed back into the time medium. Matter and energy are not being created nor destroyed, but transferred, as time gives rise to and changes space and particularly all else therein. There is not a space-time, because space itself emerges out of time, as time gives rise to space. This is also why events perceived from within space, appear to "move forward in time", wheras time itself does not have spacial dimensions, but causal dimensions and mechanism by which space both exists and is transformed, including provision and alteration of matter and energy.

    The original blog post asks: "Related to this is the question: how is the
    inside and the outside of a screen defined whilst avoiding any circular
    reasoning, and how to get a change in sign between attractive and repulsive
    effects. "

    It seems to me the natural tool for describing systems where inside and
    outside must be clearly distinguished is conformal geometric algebra
    (GA)(that is real-valued Clifford algebra with two extra dimensions which are
    used to define an origin and a point at infinity). By taking outer products
    of the regular three dimensions with the two conformal dimensions one can
    define unambiguously oriented spheres (as well as several other useful
    geometric primitives). GA has many advantages for physics such as its
    coordinate-free nature, compactness of notation, easy adaptability to all
    sorts of different problems in any dimension or signature, including those in
    relativity and quantum mechanics, and most of all, its physically meaningful
    and intuition-building descriptive power.

    An enjoyable graphical way to study and work with both the simpler 2-D and
    3-D as well as 5-D conformal GA is the free GAviewer
    software and PDF tutorials offered by Leo Dorst's group at the University of
    Amsterdam. Dorst's book on GA applications in computer science is also
    highly recommended; for those who prefer to study from more traditional
    journal-like PDFs it is worth seeking out the Cambridge GA group's papers.

    At last I can sleep well at night, without fat men around me even.
    Although not at all qualified in this field- my congratulations to solving this enormous enigma- gravity. Nobel Price in the offing, no doubt about that, especially as the theory can be and already has been tested against observable effects ( dark energy and the accelerated expansion).
    Already Platon had a hunch about the holographic principle and ever since a lot of us have "understood" that "reality" cannot be just what man observes with his proper sensory capacities.
    Recently Prof Frieden also derived the Newton laws by a similar reasoning in his Physics from Fisher information.
    I just have an uncomfortable feeling about how Time comes into this. Is it ureasonable to ask whether the "screen" is really two- dimensional or if "the information" may somehow "be stored " along a one dimensional Time coordinate, imaginary in nature evidently, as we cannot see it? Thus the bits wouls be present everywhere in space.

    The nature of “Time” surely is one of the remaining uncharted phenomena in the heavens and I was pleased to find that a description of it may possibly be found from your theory.
    Take the equation
    NkBT/2=Mc^2
    and rearrange it to
    1/kb=nN/(2Mc^2)
    Now using Wick rotation, we replace 1/kbT by it/h:
    it/h=N/(2Mc^2)
    calling i*t τ we get
    τ=N* h/(2Mc^2)
    τ, of course is the famous “imaginary” time. Suppose now τ is in fact the “real” total time, i.e the Time that we live with, and then τ is simply the collection of bits and the location of all the holographic information.
    Indeed, from a philosophical point of view, is there any reason to store bits on a screen; a two dimensional surface, when one dimension would be perfectly adequate? Our DNA molecule is an analogy, where the bits are stored along a “string” and not on a surface. Along τ, are the bits, corresponding to “genes”, coding for real events.
    Bien evidemment, a relation between Time and Enthalpy has been intuitively “obvious” ever since Eddington. Now your theory may have led to the understanding of Time.
    So what is the relation between the “screen” and Time? Could it be that they are dual?
    Again, using your formulas:
    N=Ac^3/(Gh)
    We get
    τ=Ac/(GM)
    which links the area of the (illusory?) screen to Time and shows the mathematical dualism between τ and the screen area.
    Again, from a philosophical point of view, does it not lead to “complications” having the bits, stored on a screen physically surrounding the entire Universe? Could not such a configuration lead to (endless) discussions on whether the enthalpic force can travel faster than light, so as to act everywhere instantaneously?
    Seems better to me to have the bits present everywhere, intimately associated with space as in this hypothesis of the bits being stored along τ, the time coordinate.

    Thanks for the link, man...

    "Earth to science: holography is pulling us towards tomorrow, with or without you."

    http://www.youtube.com/watch?v=lCjWKQ08dWE

    "In the beginning God created the heaven and the earth."

    Not the best translation, but it works for me.

    Pauli Exclusion is something like a bits for acceleration exchange. Is that entropy too, I wonder.

    for me there is only one theorie what proof with every thing around us this the only thing what can be true
    in fact you have to see earth spin in a ( vacium space ) if you dont do this you never will find the clue
    if I spin a bal here on earth it does do 2 things it blow air and it suck air
    this is a simple prove when a train pass by if you stand to close you feel like it pull you to it
    well in space this is another sorry, in space this ball will greate his own gravity in the way it suck air but can't blow air
    maybe not good eneough
    okay other sample , make a line to the ball and spin it , it the same effect only with air its not so strong as the line
    this also prove why on earth not every where the gravity is the same
    and with the speed of the ball with the size of the ball you can calculate the gravity and maybe even the distance between admosfeer and the ball
    this is for me the only proof and see every day here on earth
    about black matarie ,
    it seems every thing geting farther away in space and the universe get bigger
    is it not locig that then space will exspend easyer then solid object
    this also can easy be tested here on earth
    the reason the universe get bigger I dont have a clue
    what I can think about is all this explosion in space what push it to get bigger
    and ! if its get bigger then is means behind it its weaker then the air in space

    All theories about hidden dimensions, including string theory, independently predict that gravity and electromagnetism unify in the hidden dimensions. The trick to build a warp drive is to make an electromagnetic field temporarily leave normal space-time. One way of doing it may be using the Casimir effect to create a vacuum energy deficiency which sucks an electromagnetic field out of normal spacetime (graphene would probably be the best material because it is just one atomic layer thick and yet strong enough to form major structures). Another way would be to place supraconductors very close to each other in such a way that the electromagnetic field cannot go through normal space-time, so the Meisner effect forces the electromagnetic field into hidden dimensions. The technology could be used both for warp drive, wormhole construction, and cheap, safe, environmentally friendly spacelaunches.

    In 1994, Miguel Alcubierre proved theoretically that warp drive,
    expanding spacetime behind a spacecraft and contracting spacetime in
    front of the spacecraft, do not violate relativity even faster than light.
    His original paper stated that it would require impossible amounts of
    negative energy, but that problem can be circumvented. Multiple
    scientific theories, including string theory, independently predict that
    gravity and electromagnetism unify in higher dimensions. Space-time
    thus can be manipulated by forcing an electromagnetic field to leave
    normal space-time. One idea is to use vacuum energy deficiency
    created by the Casimir effect to "suck" an electromagnetic field out of
    normal spacetime (graphene is ideal for generating Casimir effect),
    another is to place many supraconductors close to
    each other, blocking escape through normal space-time so that the
    Meisner effect forces the electromagnetic field out of normal space-
    time. You should test both possibilities. Of course manipulated space-
    time can not only be used for Alcubierre drive but also for cheap, safe,
    environmentally friendly spacelaunches. There is a possible problem
    that faster than light Alcubierre drive would create an event horizon
    which would generate lethal Hawking radiation, but that can be avoided
    by having several "warp engines" each contributing a slower than light
    effect, but the combined effect is faster than light (continuous warp
    metric). A continuous warp metric would have the advantage of creating
    no event horizon and thus no Hawking radiation.
    While Alcubierres original warp metric was
    represented by a single deep "trench" in front of the spacecraft and a
    single steep "slope"
    behind the spacecraft, a continuous warp metric would be represented
    by a low "plain" or a series
    of shallow "trenches" in front of the spacecraft and a high "plain" or a
    series of moderate "slopes" behind
    the spacecraft.

    Hank
    In 1994, Miguel Alcubierre proved theoretically 
    ha ha

    I didn't need to go any farther than that...
    saw Eric Verlinde in a Dutch TV program and this triggers this reIsponse, because he is really into something but does not expand his horizon far enough. Let me explain. we all think we have discovered base principles of the universe, what if we have only discovered some parts of a fallen contracted universe and that there are way more "things" to discover beyond our (mis)understandings. Geometry is basic to this, immediately of course the question arises which geometry. Hartmuth Mueller in Global Scaling considers the universe having a fractal vibratory structure where the material universe is on the knots of this (logarithmic) vibration. This immediately implies changing the vibration will create another uni-verse of better multi-verse. Indeed as Verlinde conceives there is a field of information to consider, but it's not one field it are different fields connected with fioelds inside fields, inside fields.. Only one of those fields of fields is connected with black holes, other fields have not black holes at all. One field is connected with the Einsteinian speed of light, (shauna light) other fields are connected with light having several times the speed of light as we know it (shalea light). To continue, please read my article and start going beyond old concepts and old refrains http://scr.bi/m9AbwZ starting with erasing the 25 ages old mistake of Pythagoras Comma. PS. the article is also on http://jackgreviews.com

    The Gravitational Thermal Effect that would be proportional to the magnitude of change to a particle or bulk bodies, is mainly responsible for the overall warming of our planet. The orbit of Earth has over the last two decades been gradually increasingly perturbed by the Great Planets gradually grouping together in one portion of the solar system.
    The volcanic activity on Io a moon of Jupiter, results from the referred to effect as does the out-gassing from the central interior of a comet that is freely accelerating towards the Sun.
    I would not be surprised if it is eventually found that the geyser type effects on the frozen surfaces of moons orbiting the Great Planets results from the referred to effect.
    By placing a thermometer sensitive to small changes to the infrared deep underground in a disused section of a mine could prove the veracity of the concept. I would expect that there would be slight changes coinciding with the 24 hourly rotation of the Earth relative to the varying distance to the Moon.

    http://youtu.be/NT3gmj8SwFM
    The Space-time continuum,
    The continuum method.
    The Lecture material is presented by simple language, it is equally accessible to both: students and scientists.