8 research outputs found
Meissner masses in the gCFL phase of QCD
We calculate the Meissner masses of gluons in neutral three-flavor color
superconducting matter for finite strange quark mass. In the CFL phase the
eissner masses are slowly varying function of the strange quark mass. For large
strange quark mass, in the so called gCFL phase, the Meissner masses of gluons
with colors and 8 become imaginary, indicating an instability.Comment: New Fig. 1 shows that also the masses of the gluons 3 and 8 are
imaginar
The Crystallography of Strange Quark Matter
Cold three-flavor quark matter at large (but not asymptotically large)
densities may exist as a crystalline color superconductor. We explore this
possibility by calculating the gap parameter Delta and free energy Omega(Delta)
for possible crystal structures within a Ginzburg-Landau approximation,
evaluating Omega(Delta) to order Delta^6. We develop a qualitative
understanding of what makes a crystal structure stable, and find two structures
with particularly large values of Delta and the condensation energy, within a
factor of two of those for the CFL phase known to characterize QCD at
asymptotically large densities. The robustness of these phases results in their
being favored over wide ranges of density and though it also implies that the
Ginzburg-Landau approximation is not quantitatively reliable, previous work
suggests that it can be trusted for qualitative comparisons between crystal
structures. We close with a look ahead at the calculations that remain to be
done in order to make contact with observed pulsar glitches and neutron star
cooling.Comment: 6 pages, 3 figures. Contribution to the proceedings of Strangeness in
Quark Matter 2006, UCLA. Talk given by Rishi Sharm
Influence of finite quark chemical potentials on the three flavor LOFF phase of QCD
We study in the Ginzburg-Landau approximation, the
Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase of QCD with three flavors and one
plane wave, including terms of order O(1/mu). We show that the LOFF window is
slightly enlarged, and actually splits into two different regions, one
characterized by u-s and d-u pairings and the other with d-u pairs only.Comment: 8 pages, 3 figure
Gapless phases of color-superconducting matter
We discuss gapless color superconductivity for neutral quark matter in beta
equilibrium at zero as well as at nonzero temperature. Basic properties of
gapless superconductors are reviewed. The current progress and the remaining
problems in the understanding of the phase diagram of strange quark matter are
discussed.Comment: 8 pages, 2 figures. Plenary talk at Strangeness in Quark Matter 2004
(SQM2004), Cape Town, South Africa, 15-20 September 2004. Minor correction
Photons in gapless color-flavor-locked quark matter
We calculate the Debye and Meissner masses of a gauge boson in a material
consisting of two species of massless fermions that form a condensate of Cooper
pairs. We perform the calculation as a function of temperature, for the cases
of neutral Cooper pairs and charged Cooper pairs, and for a range of parameters
including gapped quaisparticles, and ungapped quasiparticles with both
quadratic and linear dispersion relations at low energy.
Our results are relevant to the behavior of photons and gluons in the gapless
color-flavor-locked phase of quark matter. We find that the photon's Meissner
mass vanishes, and the Debye mass shows a non-monotonic temperature dependence,
and at temperatures of order the pairing gap it drops to a minimum value of
order sqrt(alpha) times the quark chemical potential. We confirm previous
claims that at zero temperature an imaginary Meissner mass can arise from a
charged gapless condensate, and we find that at finite temperature this can
also occur for a gapped condensate.Comment: 22 pages, LaTeX; expanded discussion of temperature dependenc