Future Train Wreck: Mine or Modern Physics talk Next Thursday, Jan. 26

If you are in Cambridge, MA on Thursday, Jan. 26, you can see me live at MIT in room 3-270 from...

Holiday Physics Card, 2016

Just put them in the mail on December 24...It was a fun year of thinking, whether the idea is right...

Unified Mathematical Field Theory Talk

I gave a 15 minute talk at a local Americal Physical Society Meeting.  Here is the title and...

Holiday Card 2015

Here is my holiday card for 2015, a tradition of mine going back to 1990.  Enjoy.On the back...

 Doug Sweetser Trying to be a semi-pro amateur physicist (yes I accept special relativity is right!). I _had_ my own effort to unify gravity with other forces in Nature. It ran into quite a number of technically... Read More » Blogroll

# Spinning the Interaction Story: Spin 2 (2 of 3)

Dec 12 2011 | comment(s)

The spin 2 story unfolds much like that for spin 1. The stories are so similar, I want to take a step back and take a big picture view.

<Higgs digression>
QED works so darn well because Maxwell's theory works so well. In Maxwell's EM, action happens at a distance. Working instantaneously is a great approximation. It is only when people make refined measurements that something goes amiss. It is QED that provides the corrections. This can be done because the coupling constant for EM is small. A Feynman diagram is a visual way of keeping track of the corrections that need to be made to classical theory. Later on today, much will be said about the following three Feynman diagrams:
So much action happens with with interaction term of a Lagrangian, it is easy for those not initiated into the refined arts of field theory to skip over issues. In this blog I will dive into the details of a vector current coupling which should indicate why a spin 1 field must be associated with the interaction. The next blog will follow a similar road for a set of symmetric rank 2 tensors that requires a spin 2 field. The final blog examines how charges attract or repel for either spin. Hopefully I will include critical caveats for these subjects. If not, the comments may have a pearl or two worth reading.

$q = \epsilon_0 \oint \vec{E} \cdot d \vec{S}$

# Lucky #7 Snarky Puzzle Answers

Nov 28 2011 | comment(s)

Oct 25, Gravity is a Mystery (in words, no equations)
Snarky puzzle
Is there a handedness to getting older? Is there a handedness to communication? If there is a handedness to either, how would that effect the arrow of spacetime?

The Back Story:
Clocks tick on. The universal march of time has no handedness. Put me in an isolation chamber and I will get older at the same rate as having Thanksgiving with the family. [clarification: as noted in the comments, there is no such thing as a complete isolation chamber, it is one of those unreachable ideals.]
Newtonian gravity binds us to this rock, while EM presents us with the messages from the heavens. The math of the EM is heavenly compared to Newtonian gravity. Let's review some of the flaws in that old but still useful approach to gravity.
A list of eleven steps to analyzing an action will be presented. I could have added one more, but then people might think I was giving up on my physics addiction. The method will be applied to Newton's theory of gravity in this blog. The Maxwell action will be up next. Only if something acceptable comes through the set of tools I construct will I do the third blog that would make the Newtonian action more like Maxwell.

Once an action is written down, the rest is calculation. To provide structure to the discussion, I have compiled eleven steps to look at. One could add more or use less. There is nothing sacrosanct about this eleven step implementation for analysis of actions. With these caveats in mind, these are the eleven steps.
Gauge symmetry is a clear, direct idea in EM, as I will detail. This property is essential, [correction: due to redundancy found in the 4-potential description of light and not any issue of the speed of travel for the wave]. Any proposal for gravity must also have [gauge symmetry]. I will show how the Lagrangians I have discussed over the last few months do not have this property, therefore they are wrong. I have altered three titles to say "RETRACTION", including a brief explanation at the start. [Note: the corresponding YouTube video titles have also been marked.] A different Lagrangian I am toying with might have a chance, but that will be discussed at another time.

Click or skip this reading of the blog.