Electron gas.. :confused:

An electron gas is basically what it sounds like. But, in order to get a large number of electrons in a place where the pressure is great enough to hold them together in a 'gaseous' state, you have to look at a stellar atmosphere.

Keep in mind though, that the ideal gas law does not completely apply to electron gases since the energy states of fermions are limited by Pauli's exclusion principle.

If you do a web search for electron degeneracy pressure, you'll get a bunch of hits that explain it better than I do.

A Fermi gas, or Free electron gas, is a collection of non-interacting fermions. It is the quantum mechanical version of an ideal gas, for the case of fermionic particles. Electrons in metals and semiconductors can be approximately considered Fermi gases. The energy distribution of the fermions in a Fermi gas in thermal equilibrium is determined by their density, the temperature and the set of available energy states, via Fermi-Dirac statistics