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First year grad student at UC Berkeley. Here to ask naive questions.

I miss the theoretical physics stackexchange and think this whole website should be a bit more lax.


Mar
1
comment Questions on the $N=2$ superconformal algebra
Note one can define the A model even if the manifold is just Kahler.
Feb
14
awarded  Nice Question
Jan
17
comment Is mean field theory self-consistency analogous to string theory consistency?
Thanks for your answer, Lubos, things are certainly looking a bit clearer. Just because the perturbation theory is unique doesn't mean it's exact. Does summing over worldsheets include the effects of say D-branes created from the vacuum? What about tunneling effects between different vacua?
Jan
16
revised Is mean field theory self-consistency analogous to string theory consistency?
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Jan
15
revised Is mean field theory self-consistency analogous to string theory consistency?
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Jan
15
asked Is mean field theory self-consistency analogous to string theory consistency?
Jan
12
comment How can we define BF theory on a general 4-manifold?
I mean cycle in the homology sense. Let me know if you have more questions. I understand this topic quite a bit more now that it's been over a year. :)
Dec
19
comment Is the sign in the Schrodinger equation physical?
Flipping the sign is the same thing as reversing the direction of time. You can detect this microscopically if you don't also flip charges and parity. You can always detect this macroscopically via (say) the second law of thermodynamics.
Dec
16
comment What happens if the holonomy group lies in $SU(2)$ for a CY 3-fold?
Yes, since this means we have more covariantly constant spinor fields.
Dec
16
answered What happens if the holonomy group lies in $SU(2)$ for a CY 3-fold?
Dec
9
comment Why do degenerate normal modes appear as complex conjugate pairs?
One easy way to prove this is to just find all the solutions to the differential equation. I'm not sure if there is a better answer like "the second time derivative is a quadratic operator", whatever that would mean.
Dec
8
comment Third-order topological quantum phase transition in p+ip superfluid
Hmm. So any smooth perturbation of the thermodynamic potential will not change the order of the phase transition. A subquestion could be whether the difference between mean field potentials and true potentials is smooth.
Dec
5
comment Third-order topological quantum phase transition in p+ip superfluid
What does the phase diagram look like? I'm trying to figure out why they're not generic.
Dec
4
comment Third-order topological quantum phase transition in p+ip superfluid
What does it take for a phase transition to be third order?
Nov
22
revised Counting D0-D4 Bound States
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Nov
22
comment Counting D0-D4 Bound States
Good catch! Yes I do.
Nov
22
answered Counting D0-D4 Bound States
Sep
8
awarded  Nice Question
Aug
22
comment Is there a thermodynamic law or theorem that expresses how systems “break” or “change” when enough energy is added?
Normally these questions are considered by comparing some characteristic length, say the spacing between atoms in the solid, to the length of deformation. When the latter becomes large relative to the former, the thing breaks.
Aug
22
comment Is there a symmetry associated to the conservation of information?
As far as Liouville's theorem goes, this is a consequence of the symplectic form being closed. This implies that its integrals are constant under cobordism, which is a sort of local time-translation invariance for 2-cycles in the phase space that is independent of the actual Hamitonian. It is a kinematic rather than dynamic conservation somehow.