Interacting Boson System at Finite Temperature: The treatment of the lattice calculations

Abstract

We study interacting relativistic charged bosons at finite temperature and isospin density in a thermodynamically consistent mean-field approach with repulsive phi-4 and phi-6 interactions. The thermodynamics is formulated in an Extended Canonical Ensemble, in which the conserved isospin density, not the chemical potential, is the independent variable. This is essential in the condensed phase, where mu_I is fixed by condensation. With one constant fitted to the lattice pressure at T=122 MeV, the model reproduces the lattice isospin density, energy density, and trace anomaly, phi-6 being more accurate.

Comments: 5 pages, 8 figures, letter