Hyperon bulk viscosity in the presence of antikaon condensate

TL;DR

This paper studies how antikaon condensates affect hyperon bulk viscosity in neutron stars and finds that while suppressed, it still effectively dampens r-mode instabilities, impacting neutron star stability.

Contribution

It introduces the effect of antikaon condensates on hyperon bulk viscosity and its role in damping neutron star r-mode instabilities.

Findings

Hyperon bulk viscosity is suppressed by antikaon condensates.

Suppressed viscosity remains effective in damping r-mode instability.

Antikaon condensates influence neutron star oscillation stability.

Abstract

We investigate the hyperon bulk viscosity due to the non-leptonic process $n + p \rightleftharpoons p + \Lambda $ in $K^-$ condensed matter and its effect on the r-mode instability in neutron stars. We find that the hyperon bulk viscosity coefficient in the presence of antikaon condensate is suppressed compared with the case without the condensate. The suppressed hyperon bulk viscosity in the superconducting phase is still an efficient mechanism to damp the r-mode instability in neutron stars.