Pre-critical Phenomena of Two-flavor Color Superconductivity in Heated Quark Matter -- diquark-pair fluctuations and non-Fermi liquid behavior --

摘要

We investigate the fluctuations of the diquark-pair field and their effectson observables above the critical temperature $T_c$ in two-flavor colorsuperconductivity (CSC) at moderate density using a Nambu-Jona-Lasinio-typeeffective model of QCD. Because of the strong-coupling nature of the dynamics,the fluctuations of the pair field develop a collective mode, which has aprominent strength even well above T_c. We show that the collective mode isactually the soft mode of CSC. We examine the effects of the pair fluctuationson the specific heat and the quark spectrum for T above but close to T_c. Wefind that the specific heat exhibits singular behavior because of the pairfluctuations, in accordance with the general theory of second-order phasetransitions. The quarks display a typical non-Fermi liquid behavior, owing tothe coupling with the soft mode, leading to a pseudo-gap in the density ofstates of the quarks in the vicinity of the critical point. Some experimentalimplications of the precursory phenomena are also discussed.