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bio website sites.google.com/site/…
location Singapore
age 23
visits member for 2 years, 4 months
seen 48 mins ago

Bachelor degree in Physics. Interested in mathematical aspect of quantum field theory(though ironically not mathematically enlightened, but in continuous training). Getting to know some basics of topological insulators. I will probably start pursuing a Phd in theoretical physics in 2014 or 2015.

I'm spending more time on www.physicsoverflow.org


Apr
5
revised Is there a physical intuition for diamagnetic inequality?
added 169 characters in body
Apr
4
revised Is there a physical intuition for diamagnetic inequality?
added 176 characters in body
Apr
1
awarded  Autobiographer
Mar
24
comment How much merit is there in the heuristic argument of bulk-edge relation for topological insulators?
@BebopButUnsteady: But if the tranlation invariance is merely local, we have no Bloch theorem and hence no torus as the base manifold. Is there a way of fixing this?
Mar
24
comment Proof of renormalizability based on analyzing the symmetry of effective action: isn't regulator also important?
Thanks for the reply. But I don't think this is what I want. In fact I don't have a clear idea exactly what kind of answer I want. Sorry for that.
Mar
23
comment Proof of renormalizability based on analyzing the symmetry of effective action: isn't regulator also important?
@Heterotic, I mean couterterms like $S_{\infty}$ or $\Gamma_{N,\infty}$. Now after thinking abut the proof harder, I'm more confused that I'm not even sure my original question makes sense. But at least it is weird to me that in this proof the choice of regulator seems immaterial, in conflict with my memory that people often claim "dimensional regularization is essential to the renormalization of QCD, though not essential to QED."
Mar
22
asked Proof of renormalizability based on analyzing the symmetry of effective action: isn't regulator also important?
Mar
21
comment A small contradiction between periodic boundary condition and first Brilliouin zone
I don't see why periodic boundary condition is necessary of Bloch theorem. We just start on an infinite lattice and consider discrete translation symmetry we get Bloch theorem.
Mar
20
comment Topological insulators: why K-theory classification rather than homotopy classification?
Thank you!(I deleted the previous thank-you comment because I realized you hadn't finished writing) So the preparation job before doing homotopy classification(I mean, the part where we do Chern number calculation stuff etc.) is to sort out what the target manifold looks like, i.e. find out all the gapped Hamiltonian with certain symmetry constraints, and you last comment is basically saying even this preparation job is in general very hard to do, right?
Mar
20
accepted Topological insulators: why K-theory classification rather than homotopy classification?
Mar
20
comment Topological insulators: why K-theory classification rather than homotopy classification?
+1, very clear exposition. But one more follow-up question: is the band gap closing also an issue? Suppose a Hamiltonian A can be continuously deformed to another Hamiltonian B, what if all such homotopies close some band gaps, even say in the Kitaev's K-theory frame work? Shouldn't we consider A and B as topologically distinct?
Mar
19
asked Topological insulators: why K-theory classification rather than homotopy classification?
Mar
19
awarded  Nice Question
Mar
19
answered Question on derivation of Ward identity
Mar
19
comment Question on derivation of Ward identity
I'm saying for example you last term should be $J_i\epsilon^a t^a_{ij}\phi_j$, which is just a scalar, since everything is scalar on exponential, surely it will be a simple Taylor expansion.
Mar
19
comment Question on derivation of Ward identity
It seems your formulas are not entirely consistent with those in the link you gave, everything on the exponential is scalar, not matrix, look carefully at equation 10.170, all indices, including the matrix entry index of $t$, are contracted.
Mar
18
revised How much merit is there in the heuristic argument of bulk-edge relation for topological insulators?
added 4 characters in body
Mar
18
asked How much merit is there in the heuristic argument of bulk-edge relation for topological insulators?
Mar
16
comment Hall conductivity from Kubo: Bulk or edge?
This seems to be what you want: journals.aps.org/prl/abstract/10.1103/PhysRevLett.71.3697
Mar
13
comment Is there a physical intuition for diamagnetic inequality?
Thanks for the reply, and +1 for putting a proof. I am aware of this kind of proof. What I really want is something more physically pictorial, like "magnetic field curves the electron's trajectory and hence...". But I admit this might possibly be too much to ask.