Speaker
Description
We investigate the complex spectrum of the Dirac operator in 2+1-flavor
QCD, at nonzero temperature and isospin chemical potential, using the
extension of the Banks-Casher relation to the case of Complex Dirac
eigenvalues (derived for the zero-temperature, high-density limits of
QCD at nonzero isospin chemical potential), as a prescription to obtain
information on the BCS gap from the 2d density of the complex Dirac
eigenvalues.
Such study is motivated by the prediction, from perturbation theory, of
a superfluid state of $u$ and $\bar{d}$ Cooper pairs (BCS phase) at
asymptotically high isospin densities, plausibly connected via an
analytical crossover to the a phase with Bose-Einstein condensation of
charged pions at $\mu_I>=m_\pi/2$.
Further motivation comes from recent lattice observations (renormalized
Polyakov loop measurements) that indicate a decrease of the
deconfinement transition temperature as a function of \mu_I, suggesting
that the deconfinement crossover smoothly penetrates into the pion
condensation phase and thus favoring a scenario where the deconfinement
transition connects continuously to the BEC-BCS crossover in the
$(T,\mu_I)$ phase diagram.
