Article

Annales Henri Poincaré

, Volume 14, Issue 1, pp 1-36

Open Access This content is freely available online to anyone, anywhere at any time.

On the Energy-Momentum Spectrum of a Homogeneous Fermi Gas

  • Jan DerezińskiAffiliated withDepartment of Mathematical Methods in Physics, Faculty of Physics, University of Warsaw Email author 
  • , Krzysztof A. MeissnerAffiliated withInstitute of Theoretical Physics, Faculty of Physics, University of Warsaw
  • , Marcin NapiórkowskiAffiliated withDepartment of Mathematical Methods in Physics, Faculty of Physics, University of Warsaw

Abstract

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.