# Partition function

## Homework Statement

If we have a system of N independent particles and the partition function for one particle is Z_1, then is the partition function for the N particle system Z=(Z_1)^N?

## The Attempt at a Solution

I'm pretty sure that this is true for a classical system, but I'm not sure if it's true for a quantum system. Does the Pauli exclusion principle spoil this somehow?

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Even without quantum considerations, you end up with over counting if the particles are identical. See Gibb's Paradox.

Right. Sorry, I meant to write
$$Z={1\over {N!}}(Z_1)^N$$
Does that take care of over counting?

It is not true for the quantum case. The quantum case is easier handled via grand-partition function.

So in the quantum case, if we want to use the canonical ensemble, we have to calculate the whole partition function all in one shot?

Yep. But like I said, usually, you calculate the grand-partition function (which factorises neatly into a function of single particle states).