## PHYS 317 - Reading Assignment #22

**Lowercase 'n' appears multiplying both epsilon and mu in equation
(7.20). Explain what 'n' is, and why it's in each term.**
The Gibbs factor is e^{-(E-n*mu)/kT}, where
n is the number of particles in a given state. This state has energy
epsilon, so the energy for having n particles in this state is simply
E = n*epsilon. The Gibbs factor already has a factor of n*mu, so this
results in (7.20).

**Why can't epsilon be less than mu for a Bose gas?**
Because then the Gibbs factor would increase for increasing 'n', without
any bound, saying essentially that having more particles is always
more probable. This quickly blows up on you and makes your probabilities
unnormalizable.

** What is the condition on mu and kT for ``classical'' statistics to be valid (that is, Bose, Fermi, and classical statistics all agree)?**
We need mu << -kT

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