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Keith's user avatar
Keith
  • Member for 6 years, 6 months
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7 votes
2 answers
8k views

Commutation relations of the generators of the Lorentz group

7 votes
0 answers
360 views

Is there a Lagrangian $L$ (equivalently an action functional $S$) which yields the Navier-Stokes equation?

6 votes
1 answer
1k views

Composition of Lorentz transformations using generators and the Wigner rotation

6 votes
2 answers
357 views

A question about twin frog paradox

6 votes
3 answers
2k views

Confusion with the equivalence principle and inertial frames

5 votes
1 answer
1k views

Is there an "invariant" quantity for the classical Lagrangian?

5 votes
1 answer
470 views

Quantization of Klein-Gordon field between two boundaries

4 votes
1 answer
355 views

A question about the decoupling of Dirac equation in 1+1 dimension

4 votes
2 answers
1k views

Extreme confusion with the metric tensors

4 votes
1 answer
162 views

How to obtain (interacting) time-ordered correlation functions from the S-matrix - reverse of the LSZ formula?

3 votes
1 answer
184 views

What gives rise to mass gap for gluons, even if they are massless?

3 votes
0 answers
54 views

Inverting the matrix $\eta_{uv}(p^2-i\epsilon)-(1-\frac{1}{x})p_u p_v$

3 votes
1 answer
271 views

Calculating equation of motion in gauge theories: using ordinary derivatives or covariant derivatives?

3 votes
0 answers
62 views

Why do the two Euclidean Dirac 'measure's change via the same rule under local chiral transformations?

3 votes
1 answer
272 views

What does it exactly mean by right and left functional derivatives?

2 votes
2 answers
1k views

How to calculate the trace of six gamma matrices multiplied to $\gamma_5$?

2 votes
0 answers
45 views

How to show that the low energy effective bosonic sigma model is consistent : $\beta^G=\beta^B=0 \Rightarrow \beta^\phi=cnst$

2 votes
1 answer
267 views

Mott scattering cross section of an electron by a point spinless particle

2 votes
1 answer
151 views

Calculating higher-derivatives of quantum effective potential (Weinberg QFT chapter 16 problem 2)

2 votes
0 answers
122 views

Calculating the Kallen-Lehmann representation of conserved currents

2 votes
1 answer
115 views

Antifields in BV formalism - do they also have gauge transformation laws?

2 votes
1 answer
76 views

In calculating the abelian anomaly, why can't we use $D^\mu D_\mu$ as a regulator? - Weinberg QFT vol 2 p.364

2 votes
0 answers
100 views

How do I calculate the functional derivative of the EM action on the curved spacetime with respect to the metric?

2 votes
2 answers
47 views

In the context of field-theoretic constrained dynamics, do we have the freedom to choose the Lagrange multipliers to be time-independent?

2 votes
2 answers
416 views

Definition of a tensor

2 votes
1 answer
305 views

How to calculate $T_{00}$ of the energy-momentum tensor?

2 votes
1 answer
571 views

Conserved quantity of a relativistic free Lagrangian for a Lorentz boost

2 votes
0 answers
49 views

Approximating a linearized gravitational wave expression

2 votes
4 answers
1k views

What is the precise definition of a 4-vector?

2 votes
1 answer
219 views

A question about the Lagrangian for a massive or massless point particle