672 reputation
113
bio website chenchaozhao.wikispaces.com
location
age 24
visits member for 1 year, 11 months
seen May 12 at 5:39

Senior undergraduate at Beijing Normal University


Jul
2
awarded  Curious
Oct
17
awarded  Popular Question
Aug
28
awarded  Yearling
May
23
accepted Lagrangian for Goldstone mode + topological excitation
May
14
comment Why doublons and holons are not bounded in spin-1/2 Hubbard chain?
I see, thanks a lot!
May
13
comment Fermi level for the bulk of topological insulator
Yes, there are always impurities in real samples. In your question, you only need to care about whether they are electron donors or acceptors. Impurities themselves may lead to amazing effects which are more sophisticated than your question.
May
13
comment Fermi level for the bulk of topological insulator
Your question can be asked for any solids not specifically for TI. Chemical potential indicates the energy of doped atoms which are "hidden" as background in band structure calculations. For superconductors, chemical potential also lies in the superconducting gap and this chemical potential is the energy of superconducting electron pairs which are also "hidden as the background."
May
13
comment Why doublons and holons are not bounded in spin-1/2 Hubbard chain?
I see, thanks! Suppose I could show that in the variational ansatz, the doublon and holon were attractive to each other, will it be convincing to predict the Mott transition even though I do not scan the filling?
May
13
comment Why doublons and holons are not bounded in spin-1/2 Hubbard chain?
I calculated two-site Hubbard model and found the double occupation is $\sim (t/U)^2$. As long as $U/t$ is finite, double occupation is finte, there is no Mott transition in this sense. I argue that the dimerized ground state can be viewed as decoupled two-site Hubbard models and so there is no Mott transition. My point is that dimerization -> no Mott transition. If my arguement is false, then what's the physical mechanism that bound holons and doublons?
May
12
revised Why doublons and holons are not bounded in spin-1/2 Hubbard chain?
added 258 characters in body
May
12
asked Why doublons and holons are not bounded in spin-1/2 Hubbard chain?
Apr
17
comment How to put spin-1/2 Fermi sea into real space representation?
Thanks for the comment. When it comes to metal-mott insulator transition, we need to distinguish sites with single and double occupations. Then we have to do that with real space configurations. I should have clarified this.
Apr
16
asked How to put spin-1/2 Fermi sea into real space representation?
Mar
19
asked 2-body interaction energy of 3 particles
Feb
10
accepted Many faces of linear response theory
Feb
1
comment Proof of quantization of magnetic charge of monopoles using homotopy groups
Yet, TKNN invariant are known to be first "Chern" numbers.
Feb
1
comment Proof of quantization of magnetic charge of monopoles using homotopy groups
I see. Does it apply to all closesd 2D surfaces with non-zero curvature? e.g. a $T^2$? In this case the TKNN invariant also reads $\pi_1 (U(1)) = \mathbb Z$
Feb
1
asked Proof of quantization of magnetic charge of monopoles using homotopy groups
Jan
25
revised First Chern number, monoples and quantum Hall states
added 317 characters in body
Jan
25
comment First Chern number, monoples and quantum Hall states
Thank you for the comment. My point is that mathematical theorems are not God-given but arose from concrete problems. I was asking what was the original problem that Chern solved, from which he codified the general theorems? And Chern number seems related to vorticity and then what are the corresponding vortices in his problem?