Black holes draw audiences, because they are weird, they are profound, they are Albert Einstein and Steven Hawking rolled into a singularity. Or some such – except, none of this is actually the case. The black hole is a much more mundane concept, older than relativity, and despite much misinformation in popular and pseudo science, black holes have in a certain sense little to do with relativity (and I say this although and because I worked for many years on black holes and used general relativity when doing so).
I am currently running an experiment, with multiple aims. I have created a new blog
in wordpress, where I intend to publish a translation to modern Greek of selected articles that I have written in the past. The first attempt is already there (work is in progress, though, given my multiple occupations these days). In the blog I also offer to translate older posts on demand.
"If they would only do as he did and publish posthumously, we should all be saved a lot of trouble".
[Maurice Kendall, famous British statistician, talking of Bayesians (statisticians who employ Bayes' theorem and Bayes' approach to statistical inference, particularly related to the use of "prior beliefs") and of Bayes himself, whose groundbreaking work was only published after his death]
A group of researchers have developed what are known as vortex beams - rotating electron beams - which make it possible to investigate the magnetic properties of materials and in the future it may be possible to manipulate the tiniest components in a targeted manner and set them in rotation also.
Electron beams have been used to analyze materials for a while, such as in electron microscopes. For the most part, the beams' rotation does not affect this analysis because in classical physics, an electron current in a vacuum does not have any orbital angular momentum. But in quantum mechanics, the electrons must be envisaged as a wavelike current, which can rotate as a whole about its propagation direction, similar to the air flow in a tornado.
A very important new theoretical study
has appeared last Tuesday in the hep-ph preprint arxiv. Titled "Precise Predictions on W+4 Jet Production at the Large Hadron Collider"
, it is signed by a strong team of theorists: C. Berger, Z. Bern, L. Dixon, F. Febres Cordero, D. Forde, T. Gleisberg, H. Ita, D. Kosower, and D. Maitre.
I believe it may be quite useful if I review here the paper results, and explain to you why they are very important for the physics of the LHC. But first, I feel that there are a few details concerning the process of W+jets production at the LHC which might be obscure to most of you. Let me straighten them out -it is worthwhile to do it!Preliminaries
Does my space-plunger
sound profound? It isn’t. That space absorbs
energy is confusing talk. You could desperately try to make it work: Firstly, the “space-plunger” is not moving slowly and the energy lost is partially recovered in the kinetic energy of the expanding space. There is also energy in the gravitational potential, but it is negative, so it cancels the energy being created when a universe comes into existence. Adding all up, the total energy of the universe may be zero, if you fudge it
until you get zero. Sounds profound? It isn't.
A very important new theoretical study
appeared yesterday in the hep-ph preprint arxiv. Titled "Precise Predictions on W+4 Jet Production at the Large Hadron Collider", it is signed by a strong team of theorists: C. Berger, Z. Bern, L. Dixon, F. Febres Cordero, D. Forde, T. Gleisberg, H. Ita, D. Kosover, and D. Maitre. I will try to summarize its importance for the physics of the Large Hadron Collider in accessible terms tomorrow; for the time being I just wish to point it out for those who are capable of reading the paper but are too lazy to check the arxiv daily. I know, you belong to this set but you won't admit it!
What happens to the laws of physics if a fundamental constant turns out to be not a constant after all? The 'magic number' known as the fine-structure constant, called 'alpha' by physicists, appears to vary throughout the universe, according to a team of astrophysicists.
That means the laws of physics would vary throughout the universe also.
The arXiv preprint describes how they determined that the fine-structure constant 'alpha' varies by measuring light from a quasar as it red-shifted due to universal expansion.
To physicists, nothing is really a coincidence. Even cats in quantum boxes can be explained in mathematical terms, not to mention roulette or the success or failure of an attack in Dungeons&Dragons, but researchers at the Max Planck Institute for the Physics of Light in Erlangen say they have constructed a device that is truly random and generates random numbers that cannot be predicted in advance.
The researchers exploit the fact that measurements based on quantum physics can only produce a special result with a certain degree of probability, that is, randomly. True random numbers are needed for the secure encryption of data and to enable the reliable simulation of economic processes and changes in the climate.
Sean Carroll writes that in GR
“spacetime can give energy to matter, or absorb it from matter, so that the total energy simply isn’t conserved”.
He probably means “space” here, not “space-time”, because space-time already includes time and thus has no further time to do anything, let alone absorb stuff. Let us nevertheless do a sympathetic reading and firstly show what he may mean with a simple example: