Revisiting the boiling of primordial quark nuggets at nonzero chemical potential

Abstract

The boiling of possible quark nuggets during the quark-hadron phase transition of the Universe at nonzero chemical potential is revisited within the microscopic Brueckner–Hartree–Fock approach employed for the hadron phase, using two kinds of baryon interactions as fundamental inputs. To describe the deconfined phase of quark matter, we use a recently developed quark mass density-dependent model with a fully self-consistent thermodynamic treatment of confinement. We study the baryon number limit Aboil (above which boiling may be important) with three typical values for the confinement parameter D. It is firstly found that the baryon interaction with a softer equation of state for the hadron phase would only lead to a small increase of Aboil. However, results depend sensitively on the confinement parameter in the quark model. Specifically, boiling might be important during the Universe cooling for a limited parameter range around D1/2=170MeV, a value satisfying recent lattice QCD calculations of the vacuum chiral condensate, while for other choices of this parameter, boiling might not happen and cosmological quark nuggets of 102<A<1050 could survive.