8 research outputs found
Tricritical behavior of the massive chiral Gross-Neveu model
The phase diagram of the massive chiral Gross-Neveu model (the
1+1-dimensional Nambu-Jona-Lasinio model at large N) is investigated in the
vicinity of the tricritical point. Using the derivative expansion, the grand
canonical potential is cast into the form of a Ginzburg-Landau effective
action. Minimization of this action by variational and numerical methods
reveals both 1st and 2nd order phase transitions to a chiral crystal phase,
separated by a tricritical line. These findings are contrasted to the massive
Gross-Neveu model with discrete chiral symmetry where only 2nd order
transitions have been observed.Comment: 10 pages, 10 figures; v2: More details about perturbation theory
given, cf Eqs. (46-48
From non-degenerate conducting polymers to dense matter in the massive Gross-Neveu model
Using results from the theory of non-degenerate conducting polymers like
cis-polyacetylene, we generalize our previous work on dense baryonic matter and
the soliton crystal in the massless Gross-Neveu model to finite bare fermion
mass. In the large N limit, the exact crystal ground state can be constructed
analytically, in close analogy to the bipolaron lattice in polymers. These
findings are contrasted to the standard scenario with homogeneous phases only
and a first order phase transition at a critical chemical potential.Comment: 12 pages, 7 figures, revtex; v2: improved readability, following
advice of PRD referee; accepted for publicatio
Revised Phase Diagram of the Gross-Neveu Model
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.Comment: Revtex, 12 pages, 15 figures; v2: Axis labelling in Fig. 9 correcte
The phase diagram of the massive Gross-Neveu model, revisited
The massive Gross-Neveu model is solved in the large N limit at finite
temperature and chemical potential. The phase diagram features a kink-antikink
crystal phase which was missed in previous works. Translated into the framework
of condensed matter physics our results generalize the bipolaron lattice in
non-degenerate conducting polymers to finite temperature.Comment: revtex, 4 pages, 3 figures; v2: minor typos corrected; v3: minor
corrections concerning figures 2 and