2,406 reputation
11332
bio website berkeley.academia.edu/…
location Berkeley, CA
age 25
visits member for 3 years, 7 months
seen Dec 6 at 23:29

Currently a graduate student in mathematics at the University of California - Berkeley.

Previously obtained a MASt. in Applied Mathematics from the University of Cambridge (2013), and a B.S. in Mathematics and a B.A. in Physics from the University of Chicago (2012).


Nov
24
comment Do bad clocks measure proper time?
By definition, bad clocks do not measure proper time. The argument I gave should show that this is equivalent to 'making the world-lines of free particles locally look curved'.
Nov
24
answered Do bad clocks measure proper time?
Nov
24
revised Normalization constant of the Vacuum polarization
added 2 characters in body
Nov
22
comment Work-Energy theorem vs conservation of mechanical energy?
Sure, but this is not the integral of $-kx$, it is the integral of $-kx(s)$ with respect to s.
Nov
21
awarded  Notable Question
Nov
21
comment Work-Energy theorem vs conservation of mechanical energy?
How do you get that result for the integral? It should not be the case that $x(s)=s$. Remember, the spring itself is moving as well, so it should be the case that $s\geq x(s)$.
Nov
21
answered Work-Energy theorem vs conservation of mechanical energy?
Nov
21
reviewed Approve is it possible to flow current in open circuit?
Nov
20
awarded  Custodian
Nov
20
reviewed Reject Why do grapes in a microwave oven produce plasma?
Nov
19
answered Density matrix: error with diagonalization claim and fixing it
Nov
17
answered Is the overall force of a test charge in a electromagnetic field always the same?
Nov
14
comment A question from Schwinger's particles, sources and fields monograph
I am confused. In some places you write $\phi ^\mu$ and in others you write simply $\phi$. Is there a scalar field $\phi$ and a vector field $\phi ^\mu$?
Nov
14
comment Calculating the Sun's emitted power in a wavelength range?
See wikiwand.com/en/Stefan%E2%80%93Boltzmann_law#/… . I believe this calculation is very similar to what you would like to do.
Nov
14
comment Which renormalisation techniques are available for 3+1 QED?
You should probably distinguish between re-normalization and regularization. Pauli-Villars is a method of regularization. Two other ones that come to mind are dimensional regularization and the usual cut-off regularization.
Nov
13
revised Where does the force to stop a constant velocity object come from?
added 512 characters in body
Nov
13
answered Where does the force to stop a constant velocity object come from?
Nov
12
comment Momentum conservation in an electromagnetic system?
Well, I honestly don't know why you would need to do this. Perhaps I misunderstand your question. I thought that you took note of the fact that momentum was not conserved, and was confused as to why that was not the case. And the reason of course is because we are applying a non-zero net force to the system. As a 'sanity check', I suppose you could actually calculate the change in momentum of those three things to verify that it does indeed come out to $f\Delta t$, but given that it's so tedious to do so, I don't know why you would want to do that.
Nov
12
comment Momentum conservation in an electromagnetic system?
So in particular, it shouldn't be balanced. They should differ by $f\delta t$. Also, I admittedly don't understand why you think that the momentum of the E&M field won't change unless the top charge accelerates to a non-negligible degree. The Liénard–Wiechert depend on the velocity, which, for the bottom particle, is changing to a non-negligible degree (though I guess it's possible that you might find this dependence 'cancels' when you do the actual computation).
Nov
12
comment Momentum conservation in an electromagnetic system?
. . . Then the momentum change of the E&M field would just have to be so that, after you add these three together, you get $f\Delta t$.