2008/06/30 by Mark G. Alford, Mark Alford, Matt Braby +1 · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #High-Energy Particle Collisions Research #Pulsars and Gravitational Waves Research #astro-ph #hep-ph #nucl-th
paper · pdf · doi:10.1088/0954-3899/35/11/115007
published as J.Phys.G35:115007,2008 · 23 pages, 8 figures, v2: references added; minor rephrasings in the conclusions; version to appear in J. Phys. G
arxiv created 2008/09/03 · openalex publication_date 2008/09/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Color-flavor locked (CFL) quark matter at high densities is a color superconductor, which spontaneously breaks baryon number and chiral symmetry. Its low-energy thermodynamic and transport properties are therefore dominated by the H (superfluid) boson, and the octet of pseudoscalar pseudo-Goldstone bosons of which the neutral kaon is the lightest. We study the CFL-K0 phase, in which the stress induced by the strange quark mass causes the kaons to condense, and there is an additional ultra-light "K0" Goldstone boson arising from the spontaneous breaking of isospin. We compute the bulk viscosity of matter in the CFL-K0 phase, which arises from the beta-equilibration processes K0<->H+H and K0+H<->H. We find that the bulk viscosity varies as T7, unlike the CFL phase where it is exponentially Boltzmann-suppressed by the kaon's energy gap. However, in the temperature range of relevance for r-mode damping in compact stars, the bulk viscosity in the CFL-K0 phase turns out to be even smaller than in the uncondensed CFL phase, which already has a bulk viscosity much smaller than all other known color-superconducting quark phases.