4D-TExS: A new 4D lattice-QCD equation of state with extended density coverage

¹ Department of Physics, University of Houston, Houston, TX 77204, USAl
² Department of Physics, Wuppertal University, Gaussstr. 20, D-42119, Wuppertal, Germany
³ Dipartimento di Fisica, Università di Torino and INFN Torino, Via P. Giuria 1, I-10125 Torino, Italy
⁴ Institute for Theoretical Physics, ELTE Eötvös Loránd University, Pázmány P. sétány 1/A, H-1117 Budapest, Hungary
⁵ HUN-REN-ELTE Theoretical Physics Research Group, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary

^* e-mail: jjahan@central.uh.edu

Published online: 27 January 2025

Abstract

Although calculations of QCD thermodynamics from first-principle lattice simulations are limited to zero net-density due to the fermion sign problem, several methods have been developed to extend the equation of state (EoS) to finite values of the B, Q, S chemical potentials. Taylor expansion around µ_i = 0 (i = B, Q, S) enables to cover with confidence the region up to µ_i/T < 2.5. Recently, a new method has been developed to compute a 2D EoS in the (T, µ_B) plane. It was constructed through a T -expansion scheme (TExS), based on a resummation of the Taylor expansion, and is trusted up to densities around µ_B/T = 3.5. We present here the new 4D-TExS EoS, a generalization of the TExS to all 3 chemical potentials, expected to offer a larger coverage than the 4D Taylor expansion EoS. After explaining the basics of the T -Expansion Scheme and how it is generalized to multiple dimensions, we will present results for thermodynamic observables as functions of temperature and both finite baryon and strangeness chemical potentials.