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Dec
16
reviewed Edit The Impossibility ( or Possibility) of Solving $N$-Body Problem
Dec
16
revised The Impossibility ( or Possibility) of Solving $N$-Body Problem
Insert the paper link for easier reference
Dec
11
reviewed Approve Is there an error in Susskinds' derivation of Euler-Lagrange equations?
Dec
11
reviewed Approve Does a body curve spacetime at higher velocities?
Dec
4
reviewed Approve Introducing angular momentum for the first time to a class
Dec
4
comment Questions concerning some parts of the section on one-particle states in Weinberg's first volume on QFT
@ZhengLiu, you're welcome. Yes, the basis $\beta$ is orthonormal in the sense of eq. 2.5.19. $N(p)$ must be different from 1 because the argument of the delta-function changes from the standard momentum $k$ (in eq. 2.5.5 and 2.5.14) to an arbitrary momentum $p$ in eq. 2.5.19. The text between eqns 2.5.14 and 2.5.19 works out the proportionality factor between these two delta-functions, and $N(p)$ is selected to cancel that factor.
Dec
2
reviewed Approve What really cause light/photons to appear slower in media?
Dec
2
reviewed Approve How does this “simple” electric train work?
Nov
23
reviewed Approve Ames Room, how to construct properly?
Nov
23
reviewed Approve Can causality be violated?
Nov
22
reviewed Approve What if the centripetal force were acting outward?
Nov
21
reviewed Reject Problem in deducing the equations of motion using indefinite integral
Nov
10
reviewed Approve The correspondence between real space and reciprocal space
Nov
7
comment Feynman's proof for Liénard-Wiechert's potential of a moving charge
@guillefix, think I got it. Thanks again for the catch.
Nov
7
revised Feynman's proof for Liénard-Wiechert's potential of a moving charge
minding my c's
Nov
6
comment Feynman's proof for Liénard-Wiechert's potential of a moving charge
@guillefix, thanks! I see now I got sloppy with $c$ in a couple places. (I understand better now why people set $c=1$!) I will patch it today or tomorrow. (I think I need more time than I've got right now, to avoid making another goof.)
Nov
5
comment Where's the energy in a boosted capacitor?
OK I see what you're doing. I should have read your post and previous comments more carefully before commenting; I see you've explained all this before. Sorry. Thanks for being patient.
Nov
4
comment Where's the energy in a boosted capacitor?
I think your argument is undermined by an incorrect formulation of the field energy: $\int T^{00} d^3x$ is not covariant. It should be $\int T^{0 \nu} n_\nu (\gamma d^3x)$.
Nov
1
awarded  Custodian
Nov
1
reviewed Looks OK A question on force and acceleration