Skip to content

Commit 23176f0

Browse files
committed
giving up on prolbem 4
1 parent aa78ce0 commit 23176f0

File tree

3 files changed

+11
-0
lines changed

3 files changed

+11
-0
lines changed

docs/PS3.pdf

2.57 KB
Binary file not shown.

docs/Prob4.pdf

76.5 KB
Binary file not shown.

problems/Prob4/Prob4.tex

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4,4 +4,15 @@
44

55
\section{Phase transition of Ideal Bose System}
66

7+
I think my understanding of this problem was a bit lacking. The lecture notes mention that we should, in order to find $C_V$ above $T_c$, solve the number equation for $\mu(T)$. The number equation, before any assumptions, looks like
8+
\begin{align}
9+
n(\mu, T) = \frac{1}{4\pi^2} \left( \frac{2m}{\hbar^2}\right)^{\flatfrac32} \int_0^\infty \frac{\epsilon^{\flatfrac12} \dd{\epsilon}}{e^{\beta(\epsilon - \mu)} - 1}
10+
\end{align}
11+
We also have, I think, that for $T > T_c$, no particles in the ground state. Why is this? I think this just comes out of the definition of $T_c$ as the point where $\mu = 0$: above $T_c$, $\mu < 0$. We had an expression for $n$ at $T_c$:
12+
\begin{align}
13+
n(0, T_c) &= \frac{1}{4\pi^2} \left( \frac{2m}{\hbar^2} \right)^{\flatfrac32} \int_0^\infty \frac{\epsilon^{\flatfrac12} \dd{\epsilon}}{e^{\beta(\epsilon)} - 1} \\
14+
&= \frac{1}{4\pi^2} \left( \frac{2m}{\beta \hbar^2} \right)^{\flatfrac32} \zeta (\frac{3}{2} ) \Gamma(\frac{3}{2} )
15+
\end{align}
16+
I think that ultimately the right approach to deriving the values for $C_V$ for $T > T_c$ will be to set these expressions equal, and solve for $\mu$. Then, the integrals can be done numerically, which is where I believe the somewhat odd number $3.66$ comes from.
17+
718
\end{document}

0 commit comments

Comments
 (0)