Anisotropic fluctuations in cool quark matter and the phase diagram of Quantum Chromodynamics.
In cool quark matter, at intermediate densities the excitations of single quarks are confined ("quarkyonic"). A long ranged confining potential reduces the scattering of such quarks to be essentially one dimensional. As a result the Fermi surface, which is originally isotropic, is unstable to breaking up into a set of patches, where each patch contains a chiral spiral whose longitudinal dynamics is controlled by a Wess-Zumino-Novikov-Witten (WZNW) Lagrangian. Transverse fluctuations of the chiral spirals are like those in a smectic liquid crystal, of quartic order in momenta, and disorder the system at any nonzero temperature T. The corresponding correlation lengths are exponentially large in 1/T, though, so that the many modes in the WZNW Lagrangian are light. Such a plethora of nearly massless collective modes could greatly contribute to cooling neutron stars. Moving to low density, the chiral spirals of quarkyonic matter directly evolve into the pion/kaon condensates of hadronic nuclear matter. In Nambu-Jona-Lasinio models, analysis in mean field theory finds a critical endpoint which coincides with a Lifshitz point. From general theoretical arguments, and strongly supported by the example of inhomogeneous polymers, we argue that large infrared fluctuations wipe out the Lifshitz point, and produce an intermediate region in which the chiral spirals are strongly disordered. There may be evidence for such a region from experimental measurements of fluctuations at the Relativistic Heavy Ion Collider.
Publisher URL: http://arxiv.org/abs/1801.08156