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May
27
comment How to derive electron number equation of Bogoliubov Hamiltonian using thermodynamic relations.
I suggest trying $\partial F/\partial \mu=0$.
May
10
comment Order of Monte Carlo integration and frequency summation
The order does not matter for finite discrete summations. When infinities or integrals are involved, the order may matter.
May
10
comment Should Brillouin zone be a continuous object rather than a discrete one in the thermodynamic limit?
Since functions of $k$ are not pathological, defining the Brillouin as continuous or discrete would not produce any physical difference.
May
7
comment E and B field from Time Varying Current
related: physics.stackexchange.com/q/87746
Apr
22
comment Intro to Solid State Physics
You may also wish to check out lecture notes by other professors. For example, I have found the following helpful: www-thphys.physics.ox.ac.uk/people/SteveSimon/condmat2012/…
Mar
11
comment Difference between RPA and generalized RPA
@Adam I am interested in using RPA to compute correlation functions in general. Which diagrams should be summed? How is it different in generalized RPA?
Mar
11
comment Bogoliubov transformation with a slight twist
I would add that the diagonalization is always possible because the matrix is Hermitian.
Nov
29
comment Is there a way for an astronaut to rotate?
related: physics.stackexchange.com/q/28011
Nov
20
comment Eigenvectors of the angular momentum operator $S_x$
An eigenvector $(a,b)$ represents a state that has a probability of $|a|^2$ being spin up, and a probability of $|b|^2$ being spin down. For the probabilities to sum to one, the eigenvector must be normalized.
Nov
20
comment Interpreting a Hamiltonian in terms of 'hopping' operators
What are $a$, $b$, and $\tau$?
Oct
3
comment Mean-field approximation of the disordered state of Heisenberg model
@MarkMitchison Thanks for the explanation on mean-field theory. I am interested in the dynamics, in particular the spin susceptibility. So, I would need something more than a vanishing Hamiltonian.
Oct
3
comment Mean-field approximation of the disordered state of Heisenberg model
@MarkMitchison While the magnetization at each site is zero in the disordered phase, there may still be correlation between different sites. Perhaps such correlation can be used as an order parameter? In any case, I would expect there to be a better approximation than a vanishing Hamiltonian.
Sep
1
comment Tension on pulleys Physics Question
Could you explain what are you trying to do when you write $\sin 77.32/50 = \sin 12.68/P$?
Jul
18
comment Pair annihilation - how to generaly solve these types of problems?
It may be helpful to consider the problem in a 2D plane. Then, the momenta of the photons are four unknowns; the conservation of momentum and energy gives three equations. That the photons have the same energy gives the fourth equation. The rest is simply algebra.
Jul
17
comment Pair annihilation - how to generaly solve these types of problems?
What are you trying to solve for?
Jul
9
comment Rate of twinkling of stars
How do you calculate the frequency from the size of turbulent elements?
Jun
24
comment When a moving body collides with a stationary body, far from its centre, how do you calculate the resulting spin
@StevenNoble The angular momentum prior to the collision is nonzero.
Jun
23
comment When a moving body collides with a stationary body, far from its centre, how do you calculate the resulting spin
Consider the conservation of angular momentum.
Jun
23
comment What happens if torque = 0?
The torque is zero only when $\theta=0$.
Jun
23
comment What sort of thermodynamic process is this?
Suitable constants can probably be introduced to the equation to make it dimensionally self-consistent.