Hybrid stars from the NJL model with a tensor interaction
In order to obtain the equation of state and construct hybrid stars, we calculate the thermodynamic potential in the two-flavor Nambu--Jona-Lasinio model with tensor-type four-point interaction between quarks. In addition, we impose the beta equilibrium and charge neutrality conditions on the system. We show that the tensor condensate appears at large chemical potential, however, it is difficult to hold hybrid stars with two-solar mass by using the equation of state with the tensor interaction. Although we cannot obtain the stars with two-solar mass because of the absense of the repulsive interaction, the estimated magnetic moment density is very large. Therefore, we expect that the tensor interaction descrobes the magnetic fields of compact stars.