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location Cambridge, MA
age 26
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Physics Graduate student at Harvard University.


1d
comment Do shadows have mass?
Can you explain in what cases shadows can go faster than light?
2d
comment Kerr Metric in Orthogonal form
No. No such coordinate system exists $globally$. The cross-term in the Kerr metric describes a physically important property of the Kerr metric - that it is not static. In particular, the solution is not symmetric under $t \to - t$ (which it would be if you could find a diagonal coordinate system).
2d
comment Contraction of Kronecker delta = 4
A repeated index on $\delta^\mu{}_\mu$ implies a summation (summation convention). Then what we truly mean is $\delta^\mu_\mu = \sum_{\mu=0}^3 \delta^\mu_\mu = 1+1+1+1 = 4$. More generally, it is equal to $d$, the dimension of space-time.
2d
revised Contraction of Kronecker delta = 4
added 61 characters in body
2d
comment Voltage and volume, same SI symbol, how to discern between the two?
Concepts of voltage and volume rarely show up in the same area anyway, so there's most likely no confusion. When it does appear together in more advanced settings, people just change notation - maybe ${\cal E}$ for voltage and ${\cal V}$ for volume, but there are other choices people make.
May
20
reviewed Close $AdS_2$ Black Hole
May
20
reviewed Approve Does Time change over temperature?
May
18
comment Reduction of Nambu Goto action to true degrees of freedom
It is possible. It's known as light cone quantization.
May
16
answered Deriving solution of the Renormalization Group Equation
May
13
revised Why is the mass dimension of anticommutingcoordinates $[Mass]−1/2$
edited body
May
13
answered Why is the mass dimension of anticommutingcoordinates $[Mass]−1/2$
May
11
reviewed Close Meaning of solutions of an equation of state
May
11
reviewed Close What are the structures that exist at roughly the scale of the Planck length?
May
11
reviewed Approve Pendulum on the moon, (Highschool)
May
10
comment How to construct generators and Lie Algebra for Lorentz group?
I assume that when you say translation you really mean boost?
May
10
answered How to construct generators and Lie Algebra for Lorentz group?
May
5
revised Absoluteness of Simultaneity?
edited title
May
5
reviewed Approve Kinematics question - Newton's Law of Motion
May
3
comment Singularities in the Reissner–Nordström metric
You can figure out which is a true singularity by computing a curvature invariant, such as $R_{abcd} R^{abcd}$
May
3
comment Deriving the energy-momentum tensor conservation equation in complex coordinates, Polchinski 2.4.2
$\partial_b T^{ba} = 0$ is two sets of equations - one for $a = 1$ and another for $a = 2$. The sum is only done over the $b$ index.