14,141 research outputs found
Asymptotic deconfinement in high-density QCD
We discuss QCD with two light flavors at large baryon chemical potential mu.
Color superconductivity leads to partial breaking of the color SU(3) group. We
show that the infrared physics is governed by the gluodynamics of the remaining
SU(2) group with an exponentially soft confinement scale Lambda_QCD'
Delta*exp[-a*mu/(g*Delta)], where Delta<<mu is the superconducting gap, g is
the strong coupling, and a=0.81... We estimate that at moderate baryon
densities Lambda_QCD' is O(10 MeV) or smaller. The confinement radius increases
exponentially with density, leading to "asymptotic deconfinement." The velocity
of the SU(2) gluons is small due to the large dielectric constant of the
medium.Comment: 4 pages; restructured, published versio
Pion Propagation near the QCD Chiral Phase Transition
We point out that, in analogy with spin waves in antiferromagnets, all
parameters describing the real-time propagation of soft pions at temperatures
below the QCD chiral phase transition can be expressed in terms of static
correlators. This allows, in principle, the determination of the soft pion
dispersion relation on the lattice. Using scaling and universality arguments,
we determine the critical behavior of the parameters of pion propagation. We
predict that when the critical temperature is approached from below, the pole
mass of the pion drops despite the growth of the pion screening mass. This fact
is attributed to the decrease of the pion velocity near the phase transition.Comment: 8 pages (single column), RevTeX; added references, version to be
published in PR
Domain walls of high-density QCD
We show that in very dense quark matter there must exist metastable domain
walls where the axial U(1) phase of the color-superconducting condensate
changes by 2pi. The decay rate of the domain walls is exponentially suppressed
and we compute it semiclassically. We give an estimate of the critical chemical
potential above which our analysis is under theoretical control.Comment: 4 pages; Eq. (16) corrected, 2 new references added, published
versio
Real-time pion propagation in finite-temperature QCD
We argue that in QCD near the chiral limit, at all temperatures below the
chiral phase transition, the dispersion relation of soft pions can be expressed
entirely in terms of three temperature-dependent quantities: the pion screening
mass, a pion decay constant, and the axial isospin susceptibility. The
definitions of these quantities are given in terms of equal-time (static)
correlation functions. Thus, all three quantities can be determined directly by
lattice methods. The precise meaning of the Gell-Mann--Oakes--Renner relation
at finite temperature is given.Comment: 25 pages, 2 figures; v2: discussion on the region of applicability
expanded, to be published in PR
Charged and superconducting vortices in dense quark matter
Quark matter at astrophysical densities may contain stable vortices due to
the spontaneous breaking of hypercharge symmetry by kaon condensation. We argue
that these vortices could be both charged and electrically superconducting.
Current carrying loops (vortons) could be long lived and play a role in the
magnetic and transport properties of this matter. We provide a scenario for
vorton formation in protoneutron stars.Comment: Replaced with the published version. A typographical error in Eq. 2
is correcte
Classical stability of U(1)_A domain walls in dense matter QCD
It was recently shown that there exists metastable U(1)_A domain wall
configurations in high-density QCD (\mu >> 1 GeV). In the following we will
assess the stability of such non-trivial field configurations at intermediate
densities (\mu < 1 GeV). The existence of such configurations at intermediate
densities could have interesting consequences for the physics of neutron stars
with high core density.Comment: 13 pages, 2 Postscript figures, typos correcte
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