Nonperturbative quark matter equations of state with vector interactions

TL;DR

This paper develops nonperturbative quark matter equations of state using the functional renormalization group, incorporating vector mesons, and applies them to neutron star modeling, showing the importance of vector interactions for stellar properties.

Contribution

It introduces a novel nonperturbative approach to quark matter EoSs with vector mesons using FRG, enhancing neutron star modeling accuracy.

Findings

Vector mesons significantly stiffen the quark matter EoS.

The resulting EoS can support neutron stars with masses over two solar masses.

Comparison of hybrid star models with different vector couplings shows notable differences.

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 $\omega$- and $\phi$-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 $\beta$-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.