33,145 research outputs found
Heat Fluctuations in Brownian Transducers
Heat fluctuation probability distribution function in Brownian transducers
operating between two heat reservoirs is studied. We find, both analytically
and numerically, that the recently proposed Fluctuation Theorem for Heat
Exchange [C. Jarzynski and D. K. Wojcik, Phys. Rev. Lett. 92, 230602 (2004)]
has to be modified when the coupling mechanism between both baths is
considered. We also extend such relation when external work is present. Our
work fixes the domain of applicability of the theorem in more realistic
operating systems.Comment: Comments are welcom
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
Gravitational Field of Spherical Branes
The warped solution of Einstein's equations corresponding to the spherical
brane in five-dimensional AdS is considered. This metric represents interiors
of black holes on both sides of the brane and can provide gravitational
trapping of physical fields on the shell. It is found the analytic form of the
coordinate transformations from the Schwartschild to co-moving frame that
exists only in five dimensions. It is shown that in the static coordinates
active gravitational mass of the spherical brane, in agreement with Tolman's
formula, is negative, i.e. such objects are gravitationally repulsive.Comment: Minor corrections, 8 pages, the version accepted by Mod. Phys. Lett.
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