Momentum conservation and local field corrections for the response of interacting Fermi gases

Abstract

We reanalyze the recently derived response function for interacting systems in relaxation time approximation respecting density, momentum and energy conservation. We find that momentum conservation leads exactly to the local field corrections for both cases respecting only density conservation and respecting density and energy conservation. This rewriting simplifies the former formulae dramatically. We discuss the small wave vector expansion and find that the response function shows a high frequency dependence of ${\omega }^{-5}$ which allows to fulfill higher order sum rules. The momentum conservation also resolves a puzzle about the conductivity which should only be finite in multicomponent systems.

References in corpus (3)

• Dielectric function of a two-component plasma including collisions
• General response function for interacting quantum liquids
• Dielectric properties of interacting storage ring plasmas

Cited by in corpus (6)

• Relaxation of an Electron System : Conserving Approximation
• A number-conserving linear response study of low-velocity ion stopping in a collisional magnetized classical plasma
• Dynamical local field, compressibility and frequency sum rules for quasiparticles
• Quasiparticle parameterization of meanfields, Galilei invariance and universal conserving response functions
• Femtosecond formation of collective modes due to meanfield fluctuations
• Conservative dielectric functions and electrical conductivities from the multicomponent Bhatnagar-Gross-Krook equation