Coexisting phases in the chiral transition within the Linear sigma model with quarks

TL;DR

This paper investigates the coexistence of phases during the chiral transition in quark matter, revealing that multiple conserved charges can lead to continuous transitions with stable phase coexistence, challenging the traditional first-order transition view.

Contribution

It introduces the concept of phase coexistence in the chiral transition within the Linear sigma model considering isospin conservation, offering new insights into the transition's nature.

Findings

Multiple phase coexistence regimes identified

Continuous transition possible with conserved isospin

Implications for understanding dense quark matter

Abstract

It is believed at present that the chiral transition changes from a smooth crossover to a first-order transition at low temperatures and high densities. Such regime is commonly analyzed using effective models since first principle calculations, as in lattice arrangements, are not feasible. This transition is assumed to be discontinuous, with unstable or metastable intermediate states. However, if multiple charges are simultaneously conserved the system could undergo a continuous change through a coexistence of equilibrium states. This type of transition has multiple manifestations, as in the nuclear liquid-gas transition causing the spinodal fragmentation. The coexistence of phases in the chiral transition is studied here for quark matter assuming the conservation of the isospin composition. Using the Linear sigma model with quarks several remarkable effects are found and discussed.