Problem 16.1 of Ashcroft and Mermin, assignment (b)

  • Thread starter Thread starter MathematicalPhysicist
  • Start date Start date
  • Tags Tags
    Assignment
Click For Summary
The discussion revolves around solving problem 16.1b from Ashcroft and Mermin, focusing on the equations related to collision dynamics in a system. Participants express confusion about progressing from the initial equations to finding equilibrium values for H, specifically regarding the selection of chemical potential μ(r,t) and temperature T(r,t). There is a suggestion that completing solution 16.1a may simplify the approach to 16.1b, indicating a potential dependency between the two problems. One participant attempts a solution involving integrals and variable changes to simplify the expression, but uncertainty remains about the correctness of their approach. Overall, the thread highlights a collaborative effort to tackle complex physics problems and the interconnectedness of different parts of the assignment.
MathematicalPhysicist
Science Advisor
Gold Member
Messages
4,662
Reaction score
372

Homework Statement


I am stuck in solving problem 16.1b in the attachment there's a pic with the question itself.

Homework Equations


$$(16.9) \bigg( \frac{dg(k)}{dt}\bigg)_{coll}= - \frac{[g(k)-g^0(k)]}{\tau(k)}$$
$$(13.21)g(k,t)=g^0(k)+\int_{-\infty}^t dt' \exp(-(t-t')/\tau(\epsilon(k)))\bigg(-\partial f / \partial \epsilon\bigg) \times v(k(t'))\cdot \bigg[ -eE(t')-\nabla\mu(t')-\frac{\epsilon(k)-\mu}{T}\nabla T(t')\bigg]$$.

The Attempt at a Solution


So we have:
$$(dH/dt)_{coll} = \int dk/(4\pi^3)h(k)[-(g(k)-g^0(k))]/\tau(k)$$
Not sure how to continue from here.

I mean I am supposed to choose ##\mu(r,t)## and ##T(r,t)## that will yield an equilibrium value of ##H## equal to $$(16.33) H=\int dk/(4\pi^3)h(k)g(k)$$
I am clueless how to continue from here.

ANy takers?
problem 16.1.png
 

Attachments

  • problem 16.1.png
    problem 16.1.png
    61.2 KB · Views: 647
Physics news on Phys.org
Can you possibly please post your solution to 161.a? It looks like once solution to 16.1a is completed, then the solution to 16.1b will be a modification of the solution to 16.1a
 
Dukon said:
Can you possibly please post your solution to 161.a? It looks like once solution to 16.1a is completed, then the solution to 16.1b will be a modification of the solution to 16.1a
Are you sure?
I am not even sure my solution is correct, but here goes nothing.

We have: $$(dH/dt)_{coll} = -\int dk/(4\pi^3)h(k)\bigg[ \int dk'/(2\pi)^3\{W_{k,k'}g(k)(1-g(k'))-W_{k',k}g(k')(1-g(k))\}\bigg]$$
Let's change variables in the second integral between ##k\leftrightarrow k'## and use the fact that ##h(k)=h(k')## to get that the second term is the same as the first, and because its a difference between the two, the RHS is zero.
 

Similar threads

  • · Replies 0 ·
Replies
0
Views
2K
Replies
1
Views
2K
Replies
4
Views
592
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
8
Views
2K
Replies
1
Views
3K