skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Bulk viscosity of spin-one color superconductors with two quark flavors

Abstract

We consider the contribution of the Urca-type processes to the bulk viscosity of several spin-one color-superconducting phases of dense two-flavor quark matter. In the so-called transverse phases which are suggested to be energetically favorable at asymptotic densities, the presence of ungapped quasiparticle modes prevents that spin-one color superconductivity has a large effect on the bulk viscosity. When all modes are gapped, as for one particular color-spin-locked phase, the effect on the viscosity can be quite large, which may have important phenomenological implications.

Authors:
 [1];  [2];  [3];  [2];  [4]
  1. Frankfurt International Graduate School for Science, J.W. Goethe-Universitaet, D-60438 Frankfurt (Germany)
  2. Frankfurt Institute for Advanced Studies, J.W. Goethe-Universitaet, D-60438 Frankfurt (Germany)
  3. (United States)
  4. (Germany)
Publication Date:
OSTI Identifier:
21020195
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevD.75.065016; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COLOR MODEL; DENSITY; FLAVOR MODEL; NEUTRON STARS; QUANTUM CHROMODYNAMICS; QUARK MATTER; QUARKS; SPIN; SUPERCONDUCTIVITY; SUPERCONDUCTORS; VISCOSITY

Citation Formats

Sa'd, Basil A., Shovkovy, Igor A., Department of Physics, Western Illinois University, Macomb, Illinois 61455, Rischke, Dirk H., and Institut fuer Theoretische Physik, J.W. Goethe-Universitaet, D-60438 Frankfurt. Bulk viscosity of spin-one color superconductors with two quark flavors. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.065016.
Sa'd, Basil A., Shovkovy, Igor A., Department of Physics, Western Illinois University, Macomb, Illinois 61455, Rischke, Dirk H., & Institut fuer Theoretische Physik, J.W. Goethe-Universitaet, D-60438 Frankfurt. Bulk viscosity of spin-one color superconductors with two quark flavors. United States. doi:10.1103/PHYSREVD.75.065016.
Sa'd, Basil A., Shovkovy, Igor A., Department of Physics, Western Illinois University, Macomb, Illinois 61455, Rischke, Dirk H., and Institut fuer Theoretische Physik, J.W. Goethe-Universitaet, D-60438 Frankfurt. Thu . "Bulk viscosity of spin-one color superconductors with two quark flavors". United States. doi:10.1103/PHYSREVD.75.065016.
@article{osti_21020195,
title = {Bulk viscosity of spin-one color superconductors with two quark flavors},
author = {Sa'd, Basil A. and Shovkovy, Igor A. and Department of Physics, Western Illinois University, Macomb, Illinois 61455 and Rischke, Dirk H. and Institut fuer Theoretische Physik, J.W. Goethe-Universitaet, D-60438 Frankfurt},
abstractNote = {We consider the contribution of the Urca-type processes to the bulk viscosity of several spin-one color-superconducting phases of dense two-flavor quark matter. In the so-called transverse phases which are suggested to be energetically favorable at asymptotic densities, the presence of ungapped quasiparticle modes prevents that spin-one color superconductivity has a large effect on the bulk viscosity. When all modes are gapped, as for one particular color-spin-locked phase, the effect on the viscosity can be quite large, which may have important phenomenological implications.},
doi = {10.1103/PHYSREVD.75.065016},
journal = {Physical Review. D, Particles Fields},
number = 6,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • The bulk viscosity in spin-one color superconducting strange quark matter is calculated by taking into account the interplay between the nonleptonic and semileptonic week processes. In agreement with previous studies, it is found that the inclusion of the semileptonic processes may result in non-negligible corrections to the bulk viscosity in a narrow window of temperatures. The effect is generally more pronounced for pulsars with longer periods. Compared to the normal phase, however, this effect due to the semileptonic processes is less pronounced in spin-one color superconductors. Assuming that the critical temperature of the phase transition is much larger than 40more » keV, the main effect of spin-one color superconductivity in a wide range of temperatures is an overall increase of the bulk viscosity with respect to the normal phase. The corresponding enhancement factor reaches up to about 9 in the polar and A phases, about 25 in the planar phase, and about 29 in the color-spin-locked (CSL) phase. This factor is determined by the suppression of the nonleptonic rate in color superconducting matter and, therefore, may be even larger if all quark quasiparticles happen to be gapped.« less
  • We calculate the bulk viscosity of color-superconducting quark matter in the color-flavor-locked (CFL) phase. We assume that the lightest bosons are the superfluid mode H and the kaons K{sup 0} and K{sup +}, and that there is no kaon condensate. We calculate the rate of strangeness-equilibrating processes that convert kaons into superfluid modes, and the resultant bulk viscosity. We find that for oscillations with a timescale of milliseconds, at temperatures T<1 MeV, the CFL bulk viscosity is much less than that of unpaired quark matter, but at higher temperatures the bulk viscosity of CFL matter can become larger.
  • The nonleptonic weak processes s+u{yields}u+d and u+d{yields}s+u are known to dominate the dissipation mechanism responsible for the viscosity of strange quark matter in its normal phase. The rates of such processes remain unknown for many color superconducting phases of quark matter. In this paper, we partially fill up the gap by calculating the difference of the rates of the two nonleptonic weak processes in four transverse spin-one color superconducting phases of quark matter (slightly) out of {beta} equilibrium. The four phases studied are the color-spin locked phase, the polar phase, the planar phase, and the A phase. In the limitmore » of vanishing color superconducting gap, we reproduce the known results in the normal phase. In the general case, the rates are suppressed relative to the normal phase. The degree of the suppression is determined by the structure of the gap function in momentum space, which in turn is determined by the pairing pattern of quarks. At low temperatures, the rate is dominated by the ungapped modes. In this limit, the strongest suppression of the rate occurs in the color-spin-locked phase, and the weakest is in the polar phase and the A phase.« less
  • Neutrino emissivities due to direct Urca processes of several spin-one color-superconducting phases of dense quark matter are calculated. In particular, the role of anisotropies and nodes of the gap functions is analyzed. Results for the specific heat as well as for the cooling rates of the color-spin-locked, planar, polar, and A phases are presented and consequences for the physics of neutron stars are briefly discussed. Furthermore, it is shown that the A phase exhibits a helicity order, giving rise to a reflection asymmetry in the neutrino emissivity.
  • We investigate spin-one color superconductivity of a single quark flavor using the Ginzburg-Landau theory. First we examine the classic analysis of Bailin and Love and show that by restricting to the so-called inert states, it misses the true ground state in a part of the phase diagram. This suggests the use of the more general, noninert states, in particular, within three-flavor quark matter where the color neutrality constraint imposes stress on the spin-one pairing and may disfavor the symmetric color-spin-locked state. In the second part of the paper we show that, in analogy to some ferromagnetic materials, lack of space-inversionmore » symmetry leads to a new term in the Ginzburg-Landau functional, which favors a spatially nonuniform long-range ordering with a spiral structure. In color superconductors, this new parity-violating term is a tiny effect of weak-interaction physics. The modified phase diagram is determined and the corresponding ground states for all the phases constructed. At the end, we estimate the coefficient of the new term in the free energy functional, and discuss its relevance for the phenomenology of dense quark matter.« less