Damping of density oscillations from bulk viscosity in quark matter

TL;DR

This paper investigates how bulk viscosity in quark matter affects the damping of density oscillations in neutron star mergers, using theoretical models and analyzing temperature and density variations.

Contribution

It extends calculations of bulk viscosity in quark matter using MIT bag and pQCD models, highlighting its potential impact during neutron star postmerger phases.

Findings

Bulk viscosity can significantly damp density oscillations in quark matter.

Effects are relevant at temperatures up to 10 MeV and frequencies around 1 kHz.

Deconfined quark matter phases may influence postmerger dynamics.

Abstract

In this contribution, we extend the discussion about the calculation of the bulk viscosity of quark matter in the normal phase due to electroweak processes and its effect on the damping of baryon density oscillations that might occur in the coalescence of two compact stars. Employing the EoSs from the MIT bag model and perturbative quantum chromodynamics (pQCD) up to $\mathcal{O}(\alpha_s)$, we analyze our results varying densities in the range of temperatures from 0 to 10 MeV for frequencies around 1 kHz. Our estimates show that bulk viscous effects might play a relevant role during the postmerger stage if the system reaches a deconfined quark matter phase.