Phases of dense quarks at large N_{}
Abstract
In the limit of a large number of colors, N, we suggest that gauge theories can exhibit several distinct phases at nonzero temperature and quark density. Two are familiar: a cold, dilute phase of confined hadrons, where the pressure is ∼1, and a hot phase of deconfined quarks and gluons, with pressure ∼Nc2. When the quark chemical potential μ∼1, the deconfining transition temperature, T, is independent of μ. For T<T, as μ increases above the mass threshold, baryons quickly form a dense phase where the pressure is ∼N. As illustrated by a Skyrme crystal, chiral symmetry can be both spontaneously broken, and then restored, in the dense phase. While the pressure is ∼N, like that of (nonideal) quarks, the dense phase is still confined, with interactions near the Fermi surface those of baryons, and not of quarks. Thus in the chirally symmetric region, baryons near the Fermi surface are parity doubled. We suggest possible implications for the phase diagram of QCD.
 Publication:

Nuclear Physics A
 Pub Date:
 November 2007
 DOI:
 10.1016/j.nuclphysa.2007.08.013
 arXiv:
 arXiv:0706.2191
 Bibcode:
 2007NuPhA.796...83M
 Keywords:

 21.65.Qr;
 25.75.Nq;
 12.38.Mh;
 11.15.Pg;
 11.10.Wx;
 21.65.Mn;
 Quark matter;
 Quark deconfinement quarkgluon plasma production and phase transitions;
 Quarkgluon plasma;
 Expansions for large numbers of components;
 Finitetemperature field theory;
 Equations of state of nuclear matter;
 High Energy Physics  Phenomenology
 EPrint:
 23 pages, 2 figures, uses entcs macro. Minor changes in wording