35,745 research outputs found
Deconfinement and chiral restoration in nonlocal SU(3) chiral quark models
We study the features of nonlocal SU(3) chiral quark models with wave
function renormalization. Model parameters are determined from meson
phenomenology, considering different nonlocal form factor shapes. In this
context we analyze the characteristics of the deconfinement and chiral
restoration transitions at finite temperature, introducing the couplings of
fermions to the Polyakov loop. We analyze the results obtained for various
thermodynamical quantities considering different Polyakov loop potentials and
nonlocal form factors, in comparison with data obtained from lattice QCD
calculations.Comment: 25 pages, 5 figures. Discussion of results enlarged, figures
modified, references added. Version to appear in Physical Review
Inhomogeneous phases in nonlocal chiral quark models
The presence of inhomogeneous phases in the QCD phase diagram is analyzed
within chiral quark models that include nonlocal interactions. We work at the
mean field level, assuming that the spatial dependence of scalar and
pseudo-scalar condensates is given by a dual chiral density wave. Phase
diagrams for Gaussian nonlocal form factors are studied in detail and compared
with those obtained within the Nambu-Jona-Lasinio model and quark-meson
approaches.Comment: 14 pages, 3 figure
Generalized Ginzburg-Landau approach to inhomogeneous phases in nonlocal chiral quark models
We analyze the presence of inhomogeneous phases in the QCD phase diagram
within the framework of nonlocal chiral quark models. We concentrate in
particular in the positions of the tricritical (TCP) and Lifshitz (LP) points,
which are studied in a general context using a generalized Ginzburg-Landau
approach. We find that for all the phenomenologically acceptable model
parametrizations considered the TCP is located at a higher temperature and a
lower chemical potential in comparison with the LP. Consequently, these models
seem to favor a scenario in which the onset of the first order transition
between homogeneous phases is not covered by an inhomogeneous, energetically
favored phase.Comment: 9 pages, 1 figure. V2: Two references added, figure modified, minor
changes in the text introduced. Matches version to be published in Physics
Letters
Soliton attenuation and emergent hydrodynamics in fragile matter
Disordered packings of soft grains are fragile mechanical systems that loose
rigidity upon lowering the external pressure towards zero. At zero pressure, we
find that any infinitesimal strain-impulse propagates initially as a non-linear
solitary wave progressively attenuated by disorder. We demonstrate that the
particle fluctuations generated by the solitary-wave decay, can be viewed as a
granular analogue of temperature. Their presence is manifested by two emergent
macroscopic properties absent in the unperturbed granular packing: a finite
pressure that scales with the injected energy (akin to a granular temperature)
and an anomalous viscosity that arises even when the microscopic mechanisms of
energy dissipation are negligible. Consistent with the interpretation of this
state as a fluid-like thermalized state, the shear modulus remains zero.
Further, we follow in detail the attenuation of the initial solitary wave
identifying two distinct regimes : an initial exponential decay, followed by a
longer power law decay and suggest simple models to explain these two regimes.Comment: 8 pages, 3 Figure
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