Vector meson at non-zero baryon density and zero sound

TL;DR

This paper reports lattice simulation results of a (2+1)d four-fermion model at finite baryon density, providing evidence of zero sound, a collective excitation, through vector meson correlation functions and analytical comparisons.

Contribution

It presents the first lattice simulation evidence of zero sound in a four-fermion model at non-zero baryon density, linking numerical results with analytical solutions.

Findings

Evidence of phonon-like linear dispersion in vector meson correlations

Confirmation of zero sound as a collective excitation in lattice simulations

Consistency between numerical results and Boltzmann equation solutions

Abstract

We present simulation results of the (2+1)d four-fermion model with a baryon chemical potential. We examine temporal correlation functions of the vector meson, and find evidence of phonon-like behavior characterised by a linear dispersion relation in the long wavelength limit. We also discuss the consistency of our numerical results with analytical solutions to the Boltzmann equation corresponding to zero sound. We argue that our results provide the first evidence for a collective excitation in a lattice simulation.