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Two-flavor color superconductivity at finite temperature, chemical potential and in the presence of strong magnetic fields
Utilizing an extended two-flavor Nambu-Jona Lasinio (NJL) model, we review
some of the effects of external magnetic fields on two-flavor color
superconducting phase (2SC) at moderate baryon densities in the QCD phase
diagram. The effective action of the extended NJL model consists of two mass
gaps as functions of three intensive quantities, the temperature, the quark
chemical potential and the external magnetic field. The nonzero values of the
mass gaps, chiral and diquark condensates, induce spontaneous chiral and color
symmetry breaking, respectively, and as a result two different phases of quark
matter appear. We find the transition curves between these phases as well as
the critical points in the QCD phase diagram in terms of the intensive
quantities. Imposing a constant strong magnetic field on these two phases, we
show that the mass gaps increase with the magnetic field and the symmetry
breaking region in the QCD phase diagram expands even to the larger values of
temperature and quark chemical potential. This phenomenon is a consequence of
the magnetic catalysis of dynamical symmetry breaking, which is proven before
Universal Amplitude Ratios for Constrained Critical Systems
The critical properties of systems under constraint differ from their ideal
counterparts through Fisher renormalization. The mathematical properties of
Fisher renormalization applied to critical exponents are well known: the
renormalized indices obey the same scaling relations as the ideal ones and the
transformations are involutions in the sense that re-renormalizing the critical
exponents of the constrained system delivers their original, ideal
counterparts. Here we examine Fisher renormalization of critical amplitudes and
show that, unlike for critical exponents, the associated transformations are
not involutions. However, for ratios and combinations of amplitudes which are
universal, Fisher renormalization is involutory.Comment: JSTAT published versio
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