Bulk Features of the Quark Gluon Plasma at Finite Density

Pressure, energy density, entropy density and baryon number are the basic bulk features of quark gluon plasma (QGP), the deconfined phase of Quantum Chromodynamics (QCD). Knowledge of these quantities is a prerequisite for the successful interpretation of data from heavy ion collision experiments, and for the assessment of various effective models of quark matter. In this project we calculate the QCD equation of state at finite density in a novel expansion scheme, avoiding the shortcomings of the standard Taylor series in the chemical potential, thus circumventing the sign problem of finite density QCD for chemical potentials relevant for the RHIC Beam Energy Scan. In the first year we extrapolated the thermodynamics to finite baryon density, which was a proof of principle result [1]. In the second year we calculated the extrapolation for the actual experimental setting by enforcing strangeness neutrality. The continuum extrapolated results of the second year appeared in Ref. [2]. We also addressed the algorithmic issue of super-critical slowing down by applying parallel tempering for the quark-less case, where the transition is first order [3].