3 research outputs found
Bulk viscosity in 2SC quark matter
The bulk viscosity of three-flavor color-superconducting quark matter
originating from the nonleptonic process u+s u+d is computed. It is assumed
that up and down quarks form Cooper pairs while the strange quark remains
unpaired (2SC phase). A general derivation of the rate of strangeness
production is presented, involving contributions from a multitude of different
subprocesses, including subprocesses that involve different numbers of gapped
quarks as well as creation and annihilation of particles in the condensate. The
rate is then used to compute the bulk viscosity as a function of the
temperature, for an external oscillation frequency typical of a compact star
r-mode. We find that, for temperatures far below the critical temperature T_c
for 2SC pairing, the bulk viscosity of color-superconducting quark matter is
suppressed relative to that of unpaired quark matter, but for T >~ 10^(-3) T_c
the color-superconducting quark matter has a higher bulk viscosity. This is
potentially relevant for the suppression of r-mode instabilities early in the
life of a compact star.Comment: 18 pages + appendices (28 pages total), 8 figures; v3: corrected
numerical error in the plots; 2SC bulk viscosity is now larger than unpaired
bulk viscosity in a wider temperature rang
Bulk viscosity in nuclear and quark matter: A short review
Dong H, Su N, Wang Q. Bulk viscosity in nuclear and quark matter: A short review. J.Phys.G. 2007;34(8):S643-S646.The history and recent progresses in the study of bulk viscosity in nuclearand quark matter are reviewed. The constraints from baryon number conservationand electric neutrality in quark matter on particle densities and fluidvelocity divergences are discussed