Eur. Phys. J. Special Topics 229, 3629–3649 (2020)
https://doi.org/10.1140/epjst/e2020-000155-y

Regular Article

Nonperturbative quark matter equations of state with vector interactions

¹ Institut für Theoretische Physik, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
² LUTH, Observatoire de Paris, PSL Research University, CNRS, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France
³ Helmholtz Forschungsakademie Hessen für FAIR (HFHF), GSI Helmholtzzentrum für Schwerionenforschung, Campus Gießen, Germany

^a e-mail: bernd-jochen.schaefer@theo.physik.uni-giessen.de

Received: 11 July 2020
Accepted: 27 October 2020
Published online: 21 December 2020

Abstract

Nonperturbative equations of state (EoSs) for two and three quark flavors are constructed with the functional renormalization group (FRG) within a quark-meson model truncation augmented by vector mesons for low temperature and high density. Based on previous FRG studies without repulsive vector meson interactions the influence of isoscalar vector ω- and ϕ-mesons on the dynamical fluctuations of quarks and (pseudo)scalar mesons is investigated. The grand potential as well as vector meson condensates are evaluated as a function of quark chemical potential and the quark matter EoS in β-equilibrium is applied to neutron star (NS) physics. The tidal deformability and mass-radius relations for hybrid stars from combined hadronic and quark matter EoSs are compared for different vector couplings. We observe a significant impact of the vector mesons on the quark matter EoS such that the resulting EoS is sufficiently stiff to support two-solar-mass neutron stars.