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I'm a physics grad student just trying to figure out all this stuff like everyone else.


Jun
23
comment Why doesn't time change in the non-relativistic limit of Lorentz transformations?
@SimonLyons - $v/c$ and $v/c^2$ have different dimensions, there is no meaning to comparing them.
Jun
23
comment Why doesn't time change in the non-relativistic limit of Lorentz transformations?
Unless I am missing something how you define your coordinates, there is an error in your post - the space transformations should be $ x^1 \mapsto x^1 + v x^0 $ or $ x^1 \mapsto x^1 + v t $. Otherwise it is dimensionally incorrect.
Jun
2
comment What is the logic of not regarding perturbative renormalizability as a fundamental requirement?
A specific case of John's comment - they may be referring to asymptotic safety, also know as non-perturbative renormalizability: en.wikipedia.org/wiki/Asymptotic_safety_in_quantum_gravity
Jun
2
comment Candidates for holographic QFT of 4D Einstein gravity
Relevant/potential duplicate: physics.stackexchange.com/q/30556
May
28
comment Do we have more than one $D$ term for a single gauge group?
In arxiv.org/abs/hep-th/9603042 see eqn 2.5 and the discussion below. It seems as though the cross terms cancel (although I don't see why myself) so while the D term should strictly have both pieces in it, the cross term in $D^2$ cancels.
May
28
comment Do we have more than one $D$ term for a single gauge group?
Do you have a link to another reference that does something similar?
May
28
comment Do we have more than one $D$ term for a single gauge group?
I am inclined to agree with you. I am not a SUSY expert but it seems like the D term should have both the contributions from 6.3 and 6.6. Eqn 2.2.1 in arxiv.org/pdf/1312.2684v2.pdf seems to agree with this.
May
22
comment Reducibility of tensor products of Lorentz group representations
If you know and understand the answer now, I suggest you post it so others can benefit.
May
21
comment Reducibility of tensor products of Lorentz group representations
I am not sure what you are asking. As I read it, by 2x2 Ramond is literally saying he has 2 SU(2) alegbras. See the bottom of his page 82 - 'Suppose we clone our Lie algebra, producing two identical copies...'
May
21
comment Reducibility of tensor products of Lorentz group representations
Unfortunately I don't have Georgi handy right now. First of all, did you read chapter 33 in Scrednicki? He at least states the result you are asking about in the last couple of paragraphs of that chapter. Additionally, Ramond covers this in chapter 5 of his group theory textbook- section 5.2
May
21
comment Reducibility of tensor products of Lorentz group representations
I would recommend checking out Georgi's text in particular, he gives a nice presentation how to decompose reducible representations.
May
21
comment Reducibility of tensor products of Lorentz group representations
Relevant: physics.stackexchange.com/q/6108
May
13
comment Seiberg Duality Applications
While your question(s) is reasonable, your last sentence is quite off-putting honestly. You state`...I would like to know if it is worth the effort'. If you are interested in something go study it, if not then go find something that you are interested in. My point being as you start doing research and looking into advanced topics you will constantly confronted with this question ' is it worth it' - only you can answer that for yourself.
May
8
comment Physical question on an RLC circuit
@Carlos - your welcome, glad I could be of assistance!
May
3
comment Question Regarding Lorentz Transformation
For the velocity equation: As a general rule of thumb, equations like this should make sense in the non-relativistic limit as well. Taking this limit you would obtain $v_b = v_a - u$. Now you should be answer the question yourself...
Apr
24
comment Uncoupling a coupled oscillator Hamiltonian by change of variables
Have you verified for yourself that the ground state of a single harmonic oscillator gives you $ \hat{H} \psi_0 = E_g \psi_0$ ? If so, then since your ground state wave function is the product of two wavefunctions and your Hamiltonian is the sum of two decoupled harmonic oscillators, then your desired result should follow immediately.
Apr
7
comment What forbids the existence of a $\lambda (A^\mu A_\mu)^2$ term in the Stueckelberg action?
Note: the renormalizability is only restored in the abelian case with this trick. In the non-abelian case you have a nonlinear sigma model, which has a higher cut off, but its still non-renormalizable.
Apr
6
comment Minimal vs. Non-minimal coupling
I think its best to not get to caught up in this question in the specific context of GR. That is, look at the question in the more general context of gauge theories and effective field theory. For a discussion, see the reference: arxiv.org/abs/1305.0017
Apr
3
comment Anomalous Dimensions of Gauge Interactions
Where do they say this?
Mar
24
comment What does BICEP2's results tell us about gravitation waves and quantum gravity?
Thanks for the links.