1,364 research outputs found
Fluctuation theorem for black-body radiation
The fluctuation theorem is verified for black-body radiation, provided the
bunching of photons is taken into account appropriately.Comment: 4 pages, 3 figure
Comment on "Generalized exclusion processes: Transport coefficients"
In a recent paper Arita et al. [Phys. Rev. E 90, 052108 (2014)] consider the
transport properties of a class of generalized exclusion processes. Analytical
expressions for the transport-diffusion coefficient are derived by ignoring
correlations. It is claimed that these expressions become exact in the
hydrodynamic limit. In this Comment, we point out that (i) the influence of
correlations upon the diffusion does not vanish in the hydrodynamic limit, and
(ii) the expressions for the self- and transport diffusion derived by Arita et
al. are special cases of results derived in [Phys. Rev. Lett. 111, 110601
(2013)].Comment: (citation added, published version
Chiral Brownian heat pump
We present the exact analysis of a chiral Brownian motor and heat pump.
Optimization of the construction predicts, for a nanoscale device, frequencies
of the order of kHz and cooling rates of the order of femtojoule per second.Comment: Submitted to Phys. Rev. Let
Adsorption and desorption in confined geometries: a discrete hopping model
We study the adsorption and desorption kinetics of interacting particles
moving on a one-dimensional lattice. Confinement is introduced by limiting the
number of particles on a lattice site. Adsorption and desorption are found to
proceed at different rates, and are strongly influenced by the
concentration-dependent transport diffusion. Analytical solutions for the
transport and self-diffusion are given for systems of length 1 and 2 and for a
zero-range process. In the last situation the self- and transport diffusion can
be calculated analytically for any length.Comment: Published in EPJ ST volume "Brownian Motion in Confined Geometries
Diffusion of interacting particles in discrete geometries
We evaluate the self-diffusion and transport diffusion of interacting
particles in a discrete geometry consisting of a linear chain of cavities, with
interactions within a cavity described by a free-energy function. Exact
analytical expressions are obtained in the absence of correlations, showing
that the self-diffusion can exceed the transport diffusion if the free-energy
function is concave. The effect of correlations is elucidated by comparison
with numerical results. Quantitative agreement is obtained with recent
experimental data for diffusion in a nanoporous zeolitic imidazolate framework
material, ZIF-8.Comment: 5 pages main text (3 figures); 9 pages supplemental material (2
figures). (minor changes, published version
Fluctuation theorem for entropy production during effusion of a relativistic ideal gas
The probability distribution of the entropy production for the effusion of a
relativistic ideal gas is calculated explicitly. This result is then extended
to include particle and anti-particle pair production and annihilation. In both
cases, the fluctuation theorem is verified.Comment: 6 pages, no figure
Diffusion of interacting particles in discrete geometries: equilibrium and dynamical properties
We expand on a recent study of a lattice model of interacting particles
[Phys. Rev. Lett. 111, 110601 (2013)]. The adsorption isotherm and equilibrium
fluctuations in particle number are discussed as a function of the interaction.
Their behavior is similar to that of interacting particles in porous materials.
Different expressions for the particle jump rates are derived from transition
state theory. Which expression should be used depends on the strength of the
inter-particle interactions. Analytical expressions for the self- and transport
diffusion are derived when correlations, caused by memory effects in the
environment, are neglected. The diffusive behavior is studied numerically with
kinetic Monte Carlo (kMC) simulations, which reproduces the diffusion including
correlations. The effect of correlations is studied by comparing the analytical
expressions with the kMC simulations. It is found that the Maxwell-Stefan
diffusion can exceed the self-diffusion. To our knowledge, this is the first
time this is observed. The diffusive behavior in one-dimensional and higher
dimensional systems is qualitatively the same, with the effect of correlations
decreasing for increasing dimension. The length dependence of both the self-
and transport diffusion is studied for one-dimensional systems. For long
lengths the self-diffusion shows a one over length dependence. Finally, we
discuss when agreement with experiments and simulations can be expected. The
assumption that particles in different cavities do not interact is expected to
hold quantitatively at low and medium particle concentrations, if the particles
are not strongly interacting.Comment: (18 pages, 16 figures, published version
Determination of Dark Energy by the Einstein Telescope: Comparing with CMB, BAO and SNIa Observations
A design study is currently in progress for a third generation
gravitational-wave (GW) detector called Einstein Telescope (ET). An important
kind of source for ET will be the inspiral and merger of binary neutron stars
(BNS) up to . If BNS mergers are the progenitors of short-hard
-ray bursts, then some fraction of them will be seen both
electromagnetically and through GW, so that the luminosity distance and the
redshift of the source can be determined separately. An important property of
these `standard sirens' is that they are \emph{self-calibrating}: the
luminosity distance can be inferred directly from the GW signal, with no need
for a cosmic distance ladder. Thus, standard sirens will provide a powerful
independent check of the CDM model. In previous work, estimates were
made of how well ET would be able to measure a subset of the cosmological
parameters (such as the dark energy parameter ) it will have access to,
assuming that the others had been determined to great accuracy by alternative
means. Here we perform a more careful analysis by explicitly using the
potential Planck CMB data as prior information for these other parameters. We
find that ET will be able to constrain and with accuracies and , respectively. These results are compared
with projected accuracies for the JDEM Baryon Acoustic Oscillations project and
the SNAP Type Ia supernovae observations.Comment: 28 pages, 5 figures, 5 tables; Published Versio
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