Identities in the grand canonical ensemble
We have seen that derivatives of partition functions can be used to express various quantities of interest. Derive identities for the following in terms of derivatives of the quantum-mechanical, grand canonical partition function.
1. The average number of particles in the system, N, in terms of a derivative with respect to μ.
2. The average number of particles in the system, N, in terms of a derivative with respect to the fugacity.
3. The average energy as a function of β and μ in terms of derivatives.