Who is the smartest to explain Gravitation?
900 Nobel Laureates and they were not able to explain Gravitation, the most important force in nature.
In my view the graviton must have a speed higher then the speed of light; the gravitons with the speed of light will not escape a black hole.
General ...
@StanShunpike You are not "representing the Lorentz group with a bispinor". There is the space of bispinors, and there is a map from the Lorentz group into the matrices on that space (the representation map) so that we can speak of the Lorentz group "acting" on the bispinors (by applying the corresponding matrix)
@yuggib: Hm, unless you give me that $Q,P$ also fulfill the Weyl relations and act irreducibly, I think Stone-von Neumann doesn't apply.
@ACuriousMind irreducibility is not so important...the question boils down to: Is it necessary for two operators with those properties to satisfy the Weyl relations
You might have forced that by fixing the invariant domain of definition to be the same for $P$ and $Q$ and forcing $[P,Q]$ to be also defined on the whole of $D$. The "counterexamples" I would think of (e.g. the pair of the angle/angular momentum operators for a particle confined to a circle) seem to run into trouble mainly due to the mismatched domains of the operators
Why don't we use torsion-free covariant derivatives for QM, even though we already do so in the case of GR?
In general relativity, we use the Levi-civita connection, a torsion-free connection compatible with some Lorentz fibre metric on the tangent bundle. (represents a structure-group reductio...
@ACuriousMind 1) Does the torsion of a connection on a principal bundle make sense as an object? 2) If yes, what significance does the torsion of the EM cov. deriv. have?
@0celo7 1. No. To have torsion you need to have a solder form. Since soldering identifies a particular assoc. bundle with the tangent bundle, I don't think such a think should be done in a general gauge theory - the whole point is that that gauge structure is wholly unrelated to the tangent structure of the manifold. One might even say that it's is the distinguishing feature of GR that we have such a natural solder form.
I have a phenomenon in mind but can't remember the name. Without name or other keywords, I can google for the rest of my life. Where, in general, should I ask in such a case?
The concrete thing I can't remember the name of right now is the relativistic effect that alters classical gravitational ...
is the interaction between the photon and charged particle in a compton scattering interaction instantaneous?
in other words, is the scattered photon the same as the incoming one but only with another momentum/energy? or it's a different one and the original one has been absorbed and then a new photon has been emitted after some time
Why don't we use torsion-free covariant derivatives for QM, even though we already do so in the case of GR?
In general relativity, we use the Levi-civita connection, a torsion-free connection compatible with some Lorentz fibre metric on the tangent bundle. (represents a structure-group reductio...
