Problem 16.1 of Ashcroft and Mermin, assignment (b)

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SUMMARY

The discussion focuses on solving problem 16.1b from Ashcroft and Mermin, specifically addressing the equation for the collision term in the Boltzmann equation. Participants analyze the equation $$(dH/dt)_{coll} = -\int dk/(4\pi^3)h(k)\bigg[ \int dk'/(2\pi)^3\{W_{k,k'}g(k)(1-g(k'))-W_{k',k}g(k')(1-g(k))\}\bigg]$$ and seek guidance on selecting appropriate values for ##\mu(r,t)## and ##T(r,t)## to achieve equilibrium. The consensus suggests that completing the solution to 16.1a is crucial for progressing to 16.1b, as the latter is a modification of the former.

PREREQUISITES
  • Understanding of Boltzmann equations and collision terms
  • Familiarity with the concepts of equilibrium statistical mechanics
  • Knowledge of the functions ##\mu(r,t)## and ##T(r,t)## in thermodynamic contexts
  • Proficiency in mathematical techniques for integrals in multiple dimensions
NEXT STEPS
  • Review the solution to problem 16.1a in Ashcroft and Mermin
  • Study the derivation of the collision term in the Boltzmann equation
  • Explore the implications of equilibrium conditions in statistical mechanics
  • Learn about the mathematical techniques for changing variables in integrals
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Students of statistical mechanics, physicists working with kinetic theory, and anyone tackling advanced problems in quantum mechanics and thermodynamics.

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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
 

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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.
 

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