Bulk-viscous dissipation in strange quark stars and mergers

We revisit the sub-thermal bulk-viscous dissipation in strange quark matter considering all electroweak processes in the neutrino-transparent regime. The frequency-dependent bulk viscosity exhibits a strong temperature dependence and significant sensitivity to the strange quark mass. We also discuss two scenarios where bulk-viscous dissipation plays an important role: the tidal heating during the inspiral of strange quark star binaries, where bulk-viscous dissipation from non-leptonic processes, dominant at low temperatures, induces a cumulative phase shift in the gravitational waveform; and the damping of baryon density oscillations in post-merger remnants, where bulk viscosity could affect the kHz gravitational wave emission that next-generation detectors will observe. These results suggest that bulk-viscous dissipation may provide complementary information about the presence and properties of strange quark matter in dense matter through future gravitational wave observations, motivating its inclusion in the modeling of neutron star mergers.