Fluctuations and phases in baryonic matter

TL;DR

This paper investigates the phase structure of baryonic matter, emphasizing the impact of fluctuations beyond mean-field approximations, and demonstrates how these fluctuations influence phase transitions and stability.

Contribution

It systematically explores the effects of vacuum and thermal fluctuations on baryonic matter phases using the chiral nucleon-meson model and functional renormalisation group methods.

Findings

Vacuum and thermal fluctuations stabilize the hadronic phase.

Fluctuations shift the chiral restoration to higher densities.

Dynamical fluctuations further enhance phase stability.

Abstract

The phase structure of baryonic matter is investigated with focus on the role of fluctuations beyond the mean-field approximation. The prototype test case studied is the chiral nucleon-meson model, with added comments on the chiral quark-meson model. Applications to the liquid-gas phase transition in nuclear matter and extensions to dense matter are performed. The role of vacuum fluctuations and thermal excitations is systematically explored. It is pointed out that such fluctuations tend to stabilise the hadronic phase characterised by spontaneously broken chiral symmetry, shifting the chiral restoration transition to very high densities. This stabilisation effect is shown to be further enhanced by additional dynamical fluctuations treated with functional renormalisation group methods.