Revised Phase Diagram of the Gross-Neveu Model

TL;DR

This paper revises the phase diagram of the Gross-Neveu model at non-zero chemical potential, revealing a more complex structure with three phases, including a kink-antikink crystal, driven by an Overhauser instability.

Contribution

It provides the corrected phase diagram of the Gross-Neveu model, highlighting a new crystal phase and the mechanism behind baryonic matter structure at finite density.

Findings

Identification of a kink-antikink crystal phase

All phase transitions are second order

The phase structure is driven by an Overhauser instability

Abstract

We confirm earlier hints that the conventional phase diagram of the discrete chiral Gross-Neveu model in the large N limit is deficient at non-zero chemical potential. We present the corrected phase diagram constructed in mean field theory. It has three different phases, including a kink-antikink crystal phase. All transitions are second order. The driving mechanism for the new structure of baryonic matter in the Gross-Neveu model is an Overhauser type instability with gap formation at the Fermi surface.