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.
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:
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.