Quark contribution to r-mode instabilities for several phases of deconfined quark matter

TL;DR

This paper investigates how quark matter phases influence r-mode instabilities in rotating pulsars, revealing that quark viscosities significantly affect pulsar evolution and are not suppressed in certain superconducting phases.

Contribution

It demonstrates that quark contributions to viscosity are significant even in color-superconducting phases, challenging previous assumptions and impacting r-mode instability models.

Findings

Quark viscosities impact r-mode instability windows.

Quark contributions are not suppressed in fully gapped phases.

Implications for pulsar angular momentum evolution.

Abstract

R-mode instabilities lead to specific signatures in the evolution of rotating pulsars, and may provide a unique signature which can identify the phase of matter that exists in the interiors of such objects. The contributions of quarks' bulk and shear viscosities to the dissipation of r-mode instabilities are studied. It is shown that (contrary to earlier works) the quark contribution is \emph{not} fully suppressed in the presence of fully gapped color-superconducting phase due to the fact that the bulk viscosity is a resonance effect between the density oscillation on one side, and the interaction rates that try to restore $\beta$-equilibrium during these oscillations on the other. This will have an effect on the structure of the r-mode instability window and will affect the angular momentum evolution of pulsars.