2,907 research outputs found
Interplay between chiral and deconfinement phase transitions
By using the dressed Polyakov loop or dual chiral condensate as an equivalent
order parameter of the deconfinement phase transition, we investigate the
relation between the chiral and deconfinement phase transitions at finite
temperature and density in the framework of three-flavor Nambu--Jona-Lasinio
(NJL) model. It is found that in the chiral limit, the critical temperature for
chiral phase transition coincides with that of the dressed Polyakov loop in the
whole plane. In the case of explicit chiral symmetry breaking, it is
found that the phase transitions are flavor dependent. For each flavor, the
transition temperature for chiral restoration is smaller than that
of the dressed Polyakov loop in the low baryon density region
where the transition is a crossover, and, the two critical temperatures
coincide in the high baryon density region where the phase transition is of
first order. Therefore, there are two critical end points, i.e,
and at finite density. We also explain the feature of
in the case of 1st and 2nd order phase transitions,
and in the case of crossover, and expect this feature
is general and can be extended to full QCD theory.Comment: 8 pages, 12 figures, proceedings for the International Workshop on
Hot and Cold Baryonic Matter 2010, Budapest, Aug. 15-20, 201
Chiral condensate and dressed Polyakov loop in the Nambu--Jona-Lasinio model
We investigate the chiral condensate and the dressed Polyakov loop or dual
chiral condensate at finite temperature and density in two-flavor
Nambu--Jona-Lasinio model. The dressed Polyakov loop is regarded as an
equivalent order parameter of deconfinement phase transition in a confining
theory. We find the behavior of dressed Polyakov loop in absence of any
confinement mechanism is quite interesting, with only quark degrees of freedom
present, it still shows an order parameter like behavior. It is found that in
the chiral limit, the critical temperature for chiral phase transition
coincides with that of the dressed Polyakov loop in the whole plane.
In the case of explicit chiral symmetry breaking, it is found that the
transition temperature for chiral restoration is smaller than that
of the dressed Polyakov loop in the low baryon density region
where the transition is a crossover. With the increase of current quark mass
the difference between the two transition temperatures is found to be
increasing. However, the two critical temperatures coincide in the high baryon
density region where the phase transition is of first order. We give an
explanation on the feature of in the case of 1st and
2nd order phase transitions, and in the case of
crossover, and expect this feature is general and can be extended to full QCD
theory. Our result might indicate that in the case of crossover, there exists a
small region where chiral symmetry is restored but the color degrees of freedom
are still confined.Comment: 7 pages, 10 figure
Representation Class and Geometrical Invariants of Quantum States under Local Unitary Transformations
We investigate the equivalence of bipartite quantum mixed states under local
unitary transformations by introducing representation classes from a
geometrical approach. It is shown that two bipartite mixed states are
equivalent under local unitary transformations if and only if they have the
same representation class. Detailed examples are given on calculating
representation classes.Comment: 11 page
Smoothed Dissipative Particle Dynamics model for mesoscopic multiphase flows in the presence of thermal fluctuations
Thermal fluctuations cause perturbations of fluid-fluid interfaces and highly
nonlinear hydrodynamics in multiphase flows. In this work, we develop a novel
multiphase smoothed dissipative particle dynamics model. This model accounts
for both bulk hydrodynamics and interfacial fluctuations. Interfacial surface
tension is modeled by imposing a pairwise force between SDPD particles. We show
that the relationship between the model parameters and surface tension,
previously derived under the assumption of zero thermal fluctuation, is
accurate for fluid systems at low temperature but overestimates the surface
tension for intermediate and large thermal fluctuations. To analyze the effect
of thermal fluctuations on surface tension, we construct a coarse-grained Euler
lattice model based on the mean field theory and derive a semi-analytical
formula to directly relate the surface tension to model parameters for a wide
range of temperatures and model resolutions. We demonstrate that the present
method correctly models the dynamic processes, such as bubble coalescence and
capillary spectra across the interface
A Modified Oil Refining Loss Method
In certain research studies involving the determination of the refining loss of vegetable oils, such as soybean, the 500-gram samples required by the official method may not be available. The chromatographic method, while giving consistent results on a given sample, does not give results which check the official method. A modification of the official cup method was developed using a cup of special design with a 50-gram sample. Good checks with the official method were obtained. It was found that variations in evaporation losses were more important than mixing speeds in affecting results
Decision-making in a public hospital during economic crisis
Copyright © 2018 by Emerald Publishing Limited. George is the new president of a secondary hospital in Greece. As an intensive economic crisis has been occurring for many years, he has to make difficult decisions regarding how he can effectively reorganize the hospital. George is asked to investigate the current health environment and choose what changes he considers best
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