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2d
comment Fermi surface reconstruction and fermi pockets
The interior of an electron pocket is filled with electrons. The interior of a hole pocket is empty.
Apr
30
comment Cooper pairing from repulsive potential
One can study the problem by looking at the BCS gap equation. When the gap in a one-band system is $k$-independent, the gap equation has a non-trivial solution only when the interaction is attractive. If we allow the gap to be anisotropic, or consider a multiband system, even repulsive interactions can yield a non-trivial solution.
Apr
22
comment Stern-Gerlach experiment with Bosons
related: physics.stackexchange.com/questions/45877/…
Apr
21
comment Bogoliubov transformation with two pairing terms
@LarsMilz, the paper by Suhl et al., Phys. Rev. Lett. 3, 552 (1959) has the solution to the two-band BCS theory. Not sure if this is the same as your problem.
Apr
14
comment Hubbard model within mean-field: three different approaches
You may wish to look at Figure 6.1 of "Condensed matter field theory" by Altland and Simons. It talks about the three decoupling channels by Hubbard-Stratanovich transformation.
Apr
1
comment What is a marginal fermi liquid in a nutshell?
Paper in which marginal Fermi liquid is proposed: Phys. Rev. Lett. 63, 1996 (1989).
Mar
27
comment General properties of Matsubara frequency summations
@EverettYou, I just looked through your Mathematica package, and I am surprised how simple it seems. Could you briefly explain how it works? Typically calculating Matsubara sums by hand is quite a messy endeavor in contour integration for me.
Mar
27
comment How do we determine whether the tight binding model is valid for a material?
I think, in practice, people simply assume that the model works, calculate all its properties, and see to what extent they agree with experiments.
Feb
24
comment Which limit for matsubara frequency sum?
@EverettYou, this is interesting. The sum is very standard, yet I have not seen it discussed like that before. Do you have a reference for this?
Feb
10
comment What will be final velocity of three charges $q$, $q$, $2q$?
@ophelia, your first point is a typo, which I have fixed. Your second point is valid. I believe what I need to show is that $\theta$ actually converges at infinity.
Feb
10
comment What will be final velocity of three charges $q$, $q$, $2q$?
@PeterShor, I have a written a solution below that seems right, but there's something I can't prove. Is there a way to show that the shape of the triangle actually converges at infinity?
Feb
10
comment What will be final velocity of three charges $q$, $q$, $2q$?
@AnubhavGoel, $\theta$ is $\pi/6$ at $t=0$. When $B$ moves, $\theta$ changes.
Feb
10
comment What will be final velocity of three charges $q$, $q$, $2q$?
@Fire, I have updated my solution, but it isn't particularly neat. Do let me know if you find something simpler.
Feb
10
comment What will be final velocity of three charges $q$, $q$, $2q$?
@ophelia, I have included more details in my answer. Note that the numerical result has been corrected. Let me know if you still think something is incorrect.
Feb
9
comment What will be final velocity of three charges $q$, $q$, $2q$?
@AnubhavGoel, when $B$ is in the equilateral triangle, the force is not along $OB$, because of the unequal charges. This causes $\theta$ to change, until $t\rightarrow\infty$ when the force is along $OB$.
Feb
9
comment What will be final velocity of three charges $q$, $q$, $2q$?
@AnubhavGoel, if the force is not along $OB$ at $t\rightarrow\infty$, the angle $\theta$ would not be a constant.
Feb
3
comment What will be final velocity of three charges $q$, $q$, $2q$?
@AnubhavGoel, if the force is not along $OB$, the angle $\theta$ would change.
Jan
28
comment Electron self-energy calculation for a $k$-dependent interaction
You might want to check out the similar calculation for electron-phonon interaction, for example in the book by Mahan.
Jan
26
comment Charge inside a charged spherical shell
It is certainly unintuitive. However, let's say the charge $Q$ is somewhere on the left of the shell's center. Let $A$ be the part of the shell on the left of $Q$, and $B$ be those on the right. $A$ pushes $Q$ to the right, while $B$ pushes $Q$ to the left. The force by $A$ is intuitively stronger since it is nearer to $Q$. However, $B$ has more charges, and the two effects somehow cancel out exactly.
Jan
26
comment Open-source code for computing response functions
@CuriousOne, thanks, the hepforge projects look invaluable. It would be great if something similar exists for the condensed matter community too.