Vector meson condensation in a pion superfluid

TL;DR

This paper investigates the possibility of rho-meson Bose-Einstein condensation in isospin-rich matter, finding that it is suppressed or delayed due to interactions with pion condensates, supported by NJL and linear sigma models.

Contribution

It demonstrates that rho-meson condensation is unlikely at low isospin chemical potentials, providing a detailed comparison between NJL and linear sigma models for meson behavior.

Findings

Rho-meson condensation is avoided or postponed at high isospin chemical potentials.

NJL and linear sigma models show similar meson mass dependence on medium conditions.

The models' mapping clarifies conditions for quantitative agreement.

Abstract

We revisit the suggestion that charged rho-mesons undergo Bose-Einstein condensation in isospin-rich nuclear matter. Using a simple version of the Nambu-Jona-Lasinio (NJL) model, we conclude that rho-meson condensation is either avoided or postponed to isospin chemical potentials much higher than the rho-meson mass as a consequence of the repulsive interaction with the preformed pion condensate. In order to support our numerical results, we work out a linear sigma model for pions and rho-mesons, showing that the two models lead to similar patterns of medium dependence of meson masses. As a byproduct, we analyze in detail the mapping between the NJL model and the linear sigma model, focusing on conditions that must be satisfied for a quantitative agreement between the models.