Superconductivity 2SC phases

One expects the diquark condensate to dominate the physics at densities beyond the deconfinement/chiral restoration transition and below the critical temperature. Various phases are possible. E.g., the so called 2-color superconductivity (2SC) phase allows for unpaired quarks of one color. There may also exist a color-flavor locked (CFL) phase [7] for not too large value of the strange quark mass ms, for 2A > m2s/fiq, cf. [8], where the color superconductivity... 

From BCS theory it is known, that in order to form Cooper pairs at T = 0 in a dense Fermi system, the difference in the chemical potentials of the Fermions to be paired should not exceed the size of the gap. As previous calculations within this type of models have shown [24], there is a critical chemical potential for the occurrence of quark matter pf > 300 MeV and values of the gap in the region A < 150 MeV have been found. Therefore it is natural to consider the problem of the color superconducting (2SC) phase with the assumption, that quark matter is symmetric or very close to being symmetric (pu pd). 

The resulting phase diagram is shown in Fig. 5. It includes a 2-flavor color superconductivity (2SC) phase for which quarks of one color, say blue, remain unpaired. The color-flavor locking (CFL) phase [25] requires approximate SU(3) flavor symmetry and can be excluded from our discussion since strange quarks remain confined up to the highest densities occuring in a compact star configuration [24],... 

Figure 5. Phase diagram for Nj =2 quark matter in the NCQM. The critical temperature for color superconductivity (2SC phase) can be high enough for this phase to reach close to the tricritical point which shall be explored in future heavy-ion collision experiments.

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See also in sourсe #XX -- [ ]

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