394 research outputs found
Gauge invariance of the color-superconducting gap on the mass shell
The gap parameter for color superconductivity is expected to be a gauge
invariant quantity, at least on the appropriate mass shell. Computing the gap
to subleading order in the QCD coupling constant, g, we show that the prefactor
of the exponential in 1/g is gauge dependent off the mass shell, and
independent of gauge on the mass shell.Comment: 8 pages, Proceedings of the Conference on Statistical QCD, Bielefeld,
August 26 - 30, 200
Why Color-Flavor Locking is Just like Chiral Symmetry Breaking
We review how a classification into representations of color and flavor can
be used to understand the possible patterns of symmetry breaking for color
superconductivity in dense quark matter. In particular, we show how for three
flavors, color-flavor locking is precisely analogous to the usual pattern of
chiral symmetry breaking in the QCD vacuum.Comment: 9 pages, Proc. of the Judah Eisenberg Memorial Symposium, 'Nuclear
Matter, Hot and Cold', Tel Aviv, April 14 - 16, 199
The right choice of moment for anisotropic fluid dynamics
We study anisotropic fluid dynamics derived from the Boltzmann equation based
on a particular choice for the anisotropic distribution function within a
boost-invariant expansion of the fluid in one spatial dimension. In order to
close the conservation equations we need to choose an additional moment of the
Boltzmann equation. We discuss the influence of this choice of closure on the
time evolution of fluid-dynamical variables and search for the best agreement
to the solution of the Boltzmann equation in the relaxation-time approximation.Comment: 4 pages, 4 figures, proceedings for Quark Matter 201
Gluons, tadpoles, and color neutrality in a two-flavor color superconductor
Considering cold, dense quark matter with two massless quark flavors, we
demonstrate how, in a self-consistent calculation in the framework of QCD, the
condensation of Cooper pairs induces a non-vanishing background color field.
This background color field has precisely the right magnitude to cancel tadpole
contributions and thus ensures overall color neutrality of the two-flavor color
superconductor.Comment: 10 pages, contribution to the proceedings of the Erice school
"Heavy-Ion Collisions from Nuclear to Quark Matter" 200
A General Effective Theory for Dense Quark Matter
A general effective action for quark matter at nonzero temperature and/or
nonzero density is derived. Irrelevant quark modes are distinguished from
relevant quark modes, and hard from soft gluon modes, by introducing two
separate cut-offs in momentum space, one for quarks, , and one for
gluons, . Irrelevant quark modes and hard gluon modes are then
exactly integrated out in the functional integral representation of the QCD
partition function. Depending on the specific choice for and
, the resulting effective action contains well-known effective
actions for hot and/or dense quark matter, for instance the ``Hard Thermal
Loop'' (HTL) or the ``Hard Dense Loop'' (HDL) action, as well as the
high-density effective theory proposed by Hong and others.Comment: 10 pages, 6 figures, contribution to proceedings of SEWM 200
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