, Volume 14, Issue 1, pp 1-36,
Open Access This content is freely available online to anyone, anywhere at any time.
Date: 29 May 2012

On the Energy-Momentum Spectrum of a Homogeneous Fermi Gas


We consider translation-invariant quantum systems in thermodynamic limit. We argue that their energy-momentum spectra should have shapes consistent with effective models involving quasiparticles. Our main example is second quantized homogeneous interacting Fermi gas in a large cubic box with periodic boundary conditions, at zero temperature. We expect that its energy-momentum spectrum has a positive energy gap and a positive critical velocity.

Communicated by Claude Alain Pillet.