1,177 research outputs found
The QCD equation of state near T_0 within a quasi-particle model
We present a description of the equation of state of strongly interacting
matter within a quasi-particle model. The model is adjusted to lattice QCD data
near the deconfinement temperature . We compare in detail the excess
pressure at non-vanishing chemical potential and its expansion coefficients
with two-flavor lattice QCD calculations and outline prospects of the
extrapolation to large baryon density
Open Charm and Beauty at Ultrarelativistic Heavy Ion Colliders
Important goals of RHIC and LHC experiments with ion beams include the
creation and study of new forms of matter, such as the Quark Gluon Plasma.
Heavy quark production and attenuation will provide unique tomographic probes
of that matter. We predict the suppression pattern of open charm and beauty in
collisions at RHIC and LHC energies based on the DGLV formalism of
radiative energy loss. A cancelation between effects due to the
energy dependence of the high slope and heavy quark energy loss is
predicted to lead to surprising similarity of heavy quark suppression at RHIC
and LHC.Comment: 4 pages, 6 *.eps files combined into 4 figure
Cosmological Simulations on a Grid of Computers
The work presented in this paper aims at restricting the input parameter
values of the semi-analytical model used in GALICS and MOMAF, so as to derive
which parameters influence the most the results, e.g., star formation, feedback
and halo recycling efficiencies, etc. Our approach is to proceed empirically:
we run lots of simulations and derive the correct ranges of values. The
computation time needed is so large, that we need to run on a grid of
computers. Hence, we model GALICS and MOMAF execution time and output files
size, and run the simulation using a grid middleware: DIET. All the complexity
of accessing resources, scheduling simulations and managing data is harnessed
by DIET and hidden behind a web portal accessible to the users.Comment: Accepted and Published in AIP Conference Proceedings 1241, 2010,
pages 816-82
Symmetry restoration for odd-mass nuclei with a Skyrme energy density functional
In these proceedings, we report first results for particle-number and
angular-momentum projection of self-consistently blocked triaxial
one-quasiparticle HFB states for the description of odd-A nuclei in the context
of regularized multi-reference energy density functionals, using the entire
model space of occupied single-particle states. The SIII parameterization of
the Skyrme energy functional and a volume-type pairing interaction are used.Comment: 8 pages, 3 figures, workshop proceeding
Non-Central Heavy-Ion Collisions are the Place to Look for DCC
We give two reasons why we believe that non-central ultrarelativistic heavy
ion collisions are the place to look for the disoriented chiral condensates
(DCC). First, we argue that the most probable quench scenario for the formation
of DCC requires non-central collisions. Second, we show by numerical
simulations that strong electromagnetic fields of heavy ions can exert a
surprisingly large effect on the DCC domain formation through the chiral
anomaly. The effect again requires non-central collisions. Interestingly, the
result of simulations is consistent with the formation of correlated two
domains of the chiral condensate, which are aligned in space, perpendicular to
the scattering plane, but misaligned in isospin space.Comment: 4 pages (Latex), 3 embedded ps figures, espcrc1 style, talk given at
Quark Matter 97, December 97, Tsukuba, Japa
Exotic spin, charge and pairing correlations of the two-dimensional doped Hubbard model: a symmetry entangled mean-field approach
Intertwining of spin, charge and pairing correlations in the repulsive
two-dimensional Hubbard model is shown through unrestricted variational
calculations, with projected wavefunctions free of symmetry breaking. A
crossover from incommensurate antiferromagnetism to stripe order naturally
emerges in the hole-doped region when increasing the on-site coupling. Although
effective pairing interactions are identified, they are strongly fragmented in
several modes including d-wave pairing and more exotic channels related to an
underlying stripe. We demonstrate that the entanglement of a mean-field
wavefunction by symmetry restoration can largely account for interaction
effects.Comment: Minor corrections, one reference adde
Theory of correlations between ultra-cold bosons released from an optical lattice
In this paper we develop a theoretical description of the correlations
between ultra-cold bosons after free expansion from confinement in an optical
lattice. We consider the system evolution during expansion and give criteria
for a far field regime. We develop expressions for first and second order
two-point correlations based on a variety of commonly used approximations to
the many-body state of the system including Bogoliubov, meanfield decoupling,
and particle-hole perturbative solution about the perfect Mott-insulator state.
Using these approaches we examine the effects of quantum depletion and pairing
on the system correlations. Comparison with the directly calculated correlation
functions is used to justify a Gaussian form of our theory from which we
develop a general three-dimensional formalism for inhomogeneous lattice systems
suitable for numerical calculations of realistic experimental regimes.Comment: 18 pages, 11 figures. To appear in Phys. Rev. A. (few minor changes
made and typos fixed
Low energy monopole Modes of a Trapped atomic Fermi Gas
We consider the low energy collective monopole modes of a trapped weakly
interacting atomic Fermi gas in the collisionless regime. The spectrum is
calculated for varying coupling strength and chemical potential. Using an
effective Hamiltonian, we derive analytical results that agree well with
numerical calculations in various regimes. The onset of superfluidity is shown
to lead to effects such as the vanishing of the energy required to create a
Cooper molecule at a critical coupling strength and to the emergence of pair
vibration excitations. Our analysis suggests ways to experimentally detect the
presence of the superfluid phase in trapped atomic Fermi gases.Comment: 5 pages & 1 figure. Accepted for Phys. Rev. Let
Conformal invariant pomeron interaction in the perurbative QCD with large N_c
An effective non-local quantum field theory is constructed, which describes
interaction of pomerons in the high-coloured QCD. The theory includes both
splitting and merging triple pomeron vertexes and diagrams with pomeronic
loops. The Schwinger-Dyson equations for the 'physical' pomeron are written.
Conformal invariance allows to reduce the theory to the old-fashioned Gribov
pomeron theory with an infinite number of pomerons, one of which is
supercritical.Comment: 20 pages in LaTe
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