Eur. Phys. J. C (2013) 73: 2626
https://doi.org/10.1140/epjc/s10052-013-2626-0

Regular Article - Theoretical Physics

A thermodynamically consistent quasi-particle model without density-dependent infinity of the vacuum zero-point energy

¹ Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, and Department of Physics, Nanjing University, Nanjing, 210093, China
² Department of Physics, Nanjing University, Nanjing, 210093, China
³ Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing, 210093, China
⁴ State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS, Beijing, 100190, China

^* e-mail: zonghs@chenwang.nju.edu.cn

Received: 13 July 2013
Revised: 9 October 2013
Published online: 5 November 2013

Abstract

In this paper, we generalize the improved quasi-particle model proposed in Cao et al. (Phys. Lett. B 711:65, 2012) from finite temperature and zero chemical potential to the case of finite chemical potential and zero temperature, and calculate the equation of state (EOS) for (2+1) flavor Quantum Chromodynamics (QCD) at zero temperature and high density. We first calculate the partition function at finite temperature and chemical potential, then go to the limit T=0 and obtain the equation of state (EOS) for cold and dense QCD, which is important for the study of neutron stars. Furthermore, we use this EOS to calculate the quark-number density, the energy density, the quark-number susceptibility and the speed of sound at zero temperature and finite chemical potential and compare our results with the corresponding ones in the existing literature.