290 reputation
19
bio website
location
age
visits member for 1 year, 11 months
seen 2 days ago

Josephine stepped on my aircraft.


Apr
20
comment Some questions about Ward-Takahashi Identity
@soliton Can you give some explanation about your equation? Thank you!
Apr
19
comment Some questions about Ward-Takahashi Identity
Thank you for your answer. Besides, when defining mass shell, $p^{\mu}p_{\mu}=m^2$, is m the bass mass or physical mass?
Feb
3
comment Chiral edge state as topological properity of bulk state
The existance of edge is robust under disorder. While 'Chiral' means back scattering is forbidden. Can we understand the robustness as the result of the existance of 'chiral' edge mode? This way, maybe we can say all edge states of topological nontrivial state is chiral.
Feb
3
comment Chiral edge state as topological properity of bulk state
Thanks for your answer. Your second paragraph seems to explain the reason of 'gapless'. Do you have examples that edge state is not chiral?
Feb
2
comment Why quantum hall effect has chiral edge state?
Thanks a lot. I still have one puzzle in my mind. I want to understand how band inversion can change the topological invariant. For example, how does it change Z_2 invariant? thanks.
Feb
2
comment Why quantum hall effect has chiral edge state?
There is also a physical picture of band inversion to illustrate topological nontrivial state. For example, the first topological insulator proposed by Shoucheng Zhang in quantum wells. Does the 'inverted' in your reply refers to the inversion of valence and conduction bands?
Feb
2
comment Why quantum hall effect has chiral edge state?
Thanks. Yes, I know closing gap leads to quantum phase transition, which will change the topological invariant; and this is the reason surface states are always gapless.
Feb
2
comment Why quantum hall effect has chiral edge state?
I know that quantum spin hall effect and topological superconducting state also has chiral state. Is chiral state a result of bulk topological properity?
Feb
2
comment Why quantum hall effect has chiral edge state?
Thanks very much for your answer. This is quite a good point of view.
Jan
29
comment Where to learn Temperature Dependent Conductivity induced by Electron-Phonon Interaction?
@NanoPhys Thanks for your help.
Dec
13
comment What is different between resolvent and green function
See above @harken .
Dec
13
comment What is different between resolvent and green function
Statistical Mechanics of Nonequilibrium Process by Dimitri Zubarev
Oct
1
comment What does the term liquid mean in condensed matter physics?
What can 'motion' mean in quantum sense?
Oct
1
comment What does the term liquid mean in condensed matter physics?
Thanks, can you provide an example about the global order liqiud possesses and quantum liquid possesses, respectively?
Oct
1
comment Topological Order and Entanglement
Thanks. But is the definition of long/short entanglement through LU transformation equal to the definition from entanglement entropy, which says short range entanglement state gives zero entropy in large scale?
Sep
26
comment Entanglement measure to classify topological ordered states
Thanks, but what about the hierarchy FQH states, where filling factor $v=\frac{p}{q}=\frac{r^2\tilde{p}}{s^2\tilde{q}}$. The quantum dimension is not related one by one with degeneracy $\tilde{q}$.
Sep
21
comment Matrix element in quantum mechanics
Let redefine the notion: the creation operator $\phi_{k}=c_k$ if $k<k_F$; $\phi_{k}=c^+_k$ if $k>k_F$. And $\bar{\phi_k}$ to be the hermit conjugate of $\phi_k$. Then, $U=\sum_{\alpha\beta}U_{\alpha\beta}\phi_{\alpha}\bar{\phi_{\beta}}$, we can get $<\gamma|U|\delta>=U_{\gamma\delta}$ if we do in zero temperature and throw away the second term. That is correct. But what if the finite temperature case? For example, when $\gamma,\delta>k_F$, we can get $<\gamma|U|\delta>=U_{\gamma\delta}(1-f_{\gamma})(1-f_{\delta})$. Here $f$ is fermi distribution rather than $\theta$ function.
Sep
21
comment Matrix element in quantum mechanics
Thanks for your reply. Your suggestion is correct, I indeed left the excition of hole.
Sep
21
comment Matrix element in quantum mechanics
Can this question possibily origins from fermi sea as ground state? Since if we take vacuum as ground state, $<\gamma|U|\delta>=U_{\gamma\delta}$