The role of Debye mass in the chiral crossover in a strong magnetic field

In this paper,the Debye mass of quarks is investigated in the Nambu–Jona-Lasinio model at zero and nonzero chemical potentials.In a uniform plasma,the Debye mass usually behaves as a monotonous increasing function of the temperature,the chemical potential and the magnetic field.At the fixed coupling interaction G,we find that the magnetic catalysis(MC)on the occurrence of the chiral restoration could be revealed by the susceptibility of the Debye mass dmD/dT at low chemical potential and by the quantity TdmD/dT in the region of moderate densities.However,the inverse MC is realized under a thermomagnetic coupling constant G(B,T)by the behavior of the Debye mass at both zero and nonzero chemical potentials.

Landau quantization and spin polarization of cold magnetized quark matter

The magnetic field and density behaviors of various thermodynamic quantities of strange quark matter under compact star conditions are investigated in the framework of the thermodynamically self-consistent quasiparticle model.For individual species,a larger number density n_(i) leads to a larger magnetic field strength threshold that aligns all particles parallel or antiparallel to the magnetic field.Accordingly,in contrast to the finite baryon density effect which reduces the spin polarization of magnetized strange quark matter,the magnetic field effect leads to an enhancement of it.We also compute the sound velocity as a function of the baryon density and find the sound velocity shows an obvious oscillation with increasing density.Except for the oscillation,the sound velocity grows with increasing density,similar to the zero-magnetic field case,and approaches the conformal limit V_(s)^(2)=1/3 at high densities from below.