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The equation of state for two flavor QCD at finite density

S. Ejiri·C. R. Allton·S. J. Hands·O. Kaczmarek·F. Karsch·E. Laermann·C. Schmidt
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Abstract

We discuss the equation of state for QCD at non-zero temperature and density. We present results of a simulation for QCD with 2 flavors of p4-improved staggered fermions. Derivatives of $\ln {\cal Z}$ with respect to quark chemical potential $μ_q$ up to fourth order are calculated, enabling estimates of the pressure, quark number density and associated susceptibilities as functions of $μ_q$ via a Taylor series expansion. We also discuss the radius of convergence of the expansion as a function of temperature. It is found that the fluctuations in the quark number density increase in the vicinity of the phase transition temperature and the susceptibilities start to develop a pronounced peak as $μ_q$ is increased. This suggests the presence of a critical endpoint in the $(T, μ_q)$ plane.

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S. Ejiri, C. R. Allton, S. J. Hands, O. Kaczmarek, F. Karsch, E. Laermann, C. Schmidt. 2003-09-15. The equation of state for two flavor QCD at finite density. https://doi.org/10.1016/s0920-5632(03)02636-7

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