All Questions
12
questions
2
votes
1
answer
158
views
Is there a general argument for why non-dynamical degrees of freedom show up in the propagation of massless gauge bosons?
In both spin-1 and spin-2 gauge theories, the gauge bosons (e.g. the photon & gluon and the graviton respectively) have two physical degrees of freedom, which can be observed quantum mechanically ...
- 858
0
votes
0
answers
127
views
What defines the gauge group for pure gravity?
Asymptotic symmetry of space-time corresponds to diffeomorphism transformation of physical space-time, which manifests as isometry near Conformal Boundary. Asymptotic symmetry can be defined using ...
- 1,752
9
votes
2
answers
697
views
What's the importance of all four fundamental forces being "curvature"?
I've heard about how, in a gauge theory, the gauge covariant derivative of the field around a closed curve is generally not zero, and this is how you can quantify force or field strength. And that ...
- 2,475
3
votes
0
answers
56
views
Are anyons non local?
Studying anyonic statistics in 2 dimensions, I naturally thought to ask the question of whether anyons are non local, since as we braid one around another, no matter the distance between the two, one ...
- 737
1
vote
1
answer
274
views
Can we visualize the standard model fermions as a 5-dimensional matrix with only the first 3 dimensions gauged?
Standard model fermions are usually represented by columns. However the column can carry different connotation depending on the matrix operator acting on it. For example, the Dirac spinor 'column' and ...
- 4,452
8
votes
0
answers
383
views
Definition of gravity path integral?
In a non-abelian gauge theory there is a "fundamental" gauge field $A_\mu^a$ with gauge index $a$ often called connection. Although $ A_\mu^a$ is not gauge invariant, gauge invariant quantities can be ...
- 322
4
votes
0
answers
209
views
ALE Spaces as Spacetime?
I asked the following question (https://mathoverflow.net/questions/263654/instanton-moduli-space-on-ale-spaces/263816#263816) on MathOverflow, with regards to instanton moduli spaces on certain ALE ...
- 697
3
votes
0
answers
268
views
Partial Derivatives in Noncommutative Spacetime
Will the order of taking partial derivatives matter in a noncommutative spacetime?
If so, what implications will that have on the way we do gauge theory? For example, will our Lagrangian now contain ...
- 321
3
votes
0
answers
631
views
What's the physical or mathematical meaning of considering non-minimal coupling?
Why we still consider the case of non-minimal coupling? And I don't really understand the motivation of coupling.
In general relativity, the non-minimal coupling violates the principle of equivalence....
- 5,971
10
votes
3
answers
2k
views
Is there any relationship between gauge field and spin connection?
For a spinor on curved spacetime, $D_\mu$ is the covariant derivative for fermionic fields is
$$D_\mu = \partial_\mu - \frac{i}{4} \omega_{\mu}^{ab} \sigma_{ab}$$
where $\omega_\mu^{ab}$ are the spin ...
- 5,971
6
votes
1
answer
604
views
How would one expect a massive graviton to behave?
Typically, adding a mass $m$ to a gauge boson causes the boson to only be able to travel over a finite distance, $L\sim m^{-1}$, limiting the range of the associated force. For example, photons ...
- 3,492
10
votes
4
answers
2k
views
Why gauge theories have such a success?
[This question was inspired by a identical question asked on a other forum]
Note that we may morally include general relativity in the gauge theories.
We may have several (some are deliberately ...
- 17.7k