Quantum statistical mechanics
= Quantum statistical mechanics
<quantum statistical mechanics> describes equilibrium and fluctuations with <density matrices> and <traces> over a quantum <Hilbert space>. The canonical equilibrium state is $e^{-\beta H}/Z$, while particle exchange introduces $H-\mu N$ in the <grand canonical ensemble>. Noncommutativity and particle exchange distinguish it from a classical phase-space <distribution>.