Improved Schwinger-Dyson approach to pairing phenomena and QCD phase diagram

Phase structure and phase transitions in dense QCD are studied using the Cornwall-Jackiw-Tomboulis (CJT) potential in the improved ladder approximation. The gap function, the condensation energy and the structure of Cooper pairs are investigated at finite temperature and density. Due to strong coupling effects at low densities, the gap, critical temperature and their ratio deviate from the weak coupling values. It is shown that the internal structure of Cooper pairs are robust against the thermal effects, despite the fact that the pairs are strongly correlated near the critical temperature. Also, the effect of the strange quark mass, Ms on the phase diagram is examined using a simple kinematical criterion. We discuss the behavior of the unlocking line, on which the CFL turns into the 2SC, through the variation of Ms.Comment: Talk given at the Workshop on ``Finite Density QCD at Nara'', Nara, Japan, 10-12 July 200

Role of Strange Quark Mass in Pairing Phenomena in QCD

We study the dynamical effect of strange quark mass as well as kinematical one on the color-flavor unlocking transition using a NJL model. Paying a special attention to the multiplicity of gap parameters, we derive an exact formula of the effective potential for 5-gap parameters. Based on this, we discuss that the unlocking transition might be of second order rather than of first order as is predicted by a simple kinematical criterion for the unlocking.Comment: 10 pages, talk at the KIAS-APCTP International Symposium on Astro-Hadron Physics "Compact Stars: Quest for New States of Dense Matter

Dual chiral density waves in nuclear matter

We study inhomogeneous chiral phases in nuclear matter using a hadronic model with the parity doublet structure. With an extended ansatz for the dual chiral density wave off the chiral limit, we numerically determine the phase structure. A new type of dual chiral density wave where the condensate has nonvanishing space average is confirmed and it comes to occupy a wide range of low density region as the chiral invariant mass parameter is lowered.Comment: 7 pages, 5 eps figures, contribution to "QCD@Work 2018", International Workshop on QCD Theory and Experiment. 25-28 June 2018, Matera, Ital

Chiral multicritical points driven by isospin density in the Ginzburg-Landau approach

We study how a chiral tricritical point (TCP) on QCD phase diagram is affected by the imbalance of up and down quark densities (isospin density), using the generalized Ginzburg-Landau (GL) approach. The resulting phase diagram near TCP shows a rich fine structure which includes inhomogeneities of both the chiral and the charged pion condensations. It turns out that the TCP splits into multicritical points.Comment: 4 pages, 2 eps figures. Presented at QCD@Work 2012: International Workshop on QCD - Theory and Experiment, June 18-21, Lecce (Italy