Bulk viscosity in the nonlinear and anharmonic regimes of strange quark matter

The bulk viscosity of cold, dense three-flavor quark matter is studied as a function of temperature and the amplitude of density oscillations. The study is extended to the case of two different types of anharmonic oscillations of density. We point out several qualitative effects due to the anharmonicity, although quantitatively they appear to be relatively small. We found that, in most regions of the parameter space, except for very large amplitudes of density oscillations (i.e. 10% and above), nonlinear effects and anharmonicity have a small effect on the interplay of the nonleptonic and semileptonic processes in the bulk viscosity.