3,413 research outputs found
Non-equilibrium stationary state of a two-temperature spin chain
A kinetic one-dimensional Ising model is coupled to two heat baths, such that
spins at even (odd) lattice sites experience a temperature ().
Spin flips occur with Glauber-type rates generalised to the case of two
temperatures. Driven by the temperature differential, the spin chain settles
into a non-equilibrium steady state which corresponds to the stationary
solution of a master equation. We construct a perturbation expansion of this
master equation in terms of the temperature difference and compute explicitly
the first two corrections to the equilibrium Boltzmann distribution. The key
result is the emergence of additional spin operators in the steady state,
increasing in spatial range and order of spin products. We comment on the
violation of detailed balance and entropy production in the steady state.Comment: 11 pages, 1 figure, Revte
Driven lattice glass as a ratchet and pawl machine
Boundary-induced transport in particle systems with anomalous diffusion
exhibits rectification, negative resistance, and hysteresis phenomena depending
on the way the drive acts on the boundary. The solvable case of a 1D system
characterized by a power-law diffusion coefficient and coupled to two particles
reservoirs at different chemical potential is examined. In particular, it is
shown that a microscopic realisation of such a diffusion model is provided by a
3D driven lattice-gas with kinetic constraints, in which energy barriers are
absent and the local microscopic reversibility holds.Comment: 12 pages, 4 figures, minor change
Fluctuation theorems for stochastic dynamics
Fluctuation theorems make use of time reversal to make predictions about
entropy production in many-body systems far from thermal equilibrium. Here we
review the wide variety of distinct, but interconnected, relations that have
been derived and investigated theoretically and experimentally. Significantly,
we demonstrate, in the context of Markovian stochastic dynamics, how these
different fluctuation theorems arise from a simple fundamental time-reversal
symmetry of a certain class of observables. Appealing to the notion of Gibbs
entropy allows for a microscopic definition of entropy production in terms of
these observables. We work with the master equation approach, which leads to a
mathematically straightforward proof and provides direct insight into the
probabilistic meaning of the quantities involved. Finally, we point to some
experiments that elucidate the practical significance of fluctuation relations.Comment: 48 pages, 2 figures. v2: minor changes for consistency with published
versio
Non-equilibrium work relations
This is a brief review of recently derived relations describing the behaviour
of systems far from equilibrium. They include the Fluctuation Theorem,
Jarzynski's and Crooks' equalities, and an extended form of the Second
Principle for general steady states. They are very general and their proofs
are, in most cases, disconcertingly simple.Comment: Brief Summer School Lecture Note
On the relation between event-based and time-based current statistics
Current statistics can be calculated in various ways. Event-based approaches
use the statistics of the number of events occuring during a given time.
Time-based approaches use the statistics of the time needed to reach a given
number of events. By analyzing normal as well as anomalous statistics of
nonequilibrium currents through a two level system in contact with two
different reservoirs, we investigate the conditions under which these different
statistics do or do not yield identical predictions. We rely on the continuous
time random walk formulation introduced in our earlier work [Phys. Rev. E 77,
051119 (2008)].Comment: 4 pages, 1 figure; v2: accepted in EPL 89, 10008 (2010
Nonequilibrium thermodynamics as a gauge theory
We assume that markovian dynamics on a finite graph enjoys a gauge symmetry
under local scalings of the probability density, derive the transformation law
for the transition rates and interpret the thermodynamic force as a gauge
potential. A widely accepted expression for the total entropy production of a
system arises as the simplest gauge-invariant completion of the time derivative
of Gibbs's entropy. We show that transition rates can be given a simple
physical characterization in terms of locally-detailed-balanced heat
reservoirs. It follows that Clausius's measure of irreversibility along a
cyclic transformation is a geometric phase. In this picture, the gauge symmetry
arises as the arbitrariness in the choice of a prior probability. Thermostatics
depends on the information that is disposable to an observer; thermodynamics
does not.Comment: 6 pages. Non-fatal errors in eq.(6), eq.(26) and eq.(31) have been
amende
A resource of genome-wide single-nucleotide polymorphisms generated by RAD tag sequencing in the critically endangered European eel
Reduced representation genome sequencing such as restriction-site-associated DNA (RAD) sequencing is finding increased use to identify and genotype large numbers of single-nucleotide polymorphisms (SNPs) in model and nonmodel species. We generated a unique resource of novel SNP markers for the European eel using the RAD sequencing approach that was simultaneously identified and scored in a genome-wide scan of 30 individuals. Whereas genomic resources are increasingly becoming available for this species, including the recent release of a draft genome, no genome-wide set of SNP markers was available until now. The generated SNPs were widely distributed across the eel genome, aligning to 4779 different contigs and 19 703 different scaffolds. Significant variation was identified, with an average nucleotide diversity of 0.00529 across individuals. Results varied widely across the genome, ranging from 0.00048 to 0.00737 per locus. Based on the average nucleotide diversity across all loci, long-term effective population size was estimated to range between 132 000 and 1 320 000, which is much higher than previous estimates based on microsatellite loci. The generated SNP resource consisting of 82 425 loci and 376 918 associated SNPs provides a valuable tool for future population genetics and genomics studies and allows for targeting specific genes and particularly interesting regions of the eel genome
First-order dynamical phase transition in models of glasses: an approach based on ensembles of histories
We investigate the dynamics of kinetically constrained models of glass
formers by analysing the statistics of trajectories of the dynamics, or
histories, using large deviation function methods. We show that, in general,
these models exhibit a first-order dynamical transition between active and
inactive dynamical phases. We argue that the dynamical heterogeneities
displayed by these systems are a manifestation of dynamical first-order phase
coexistence. In particular, we calculate dynamical large deviation functions,
both analytically and numerically, for the Fredrickson-Andersen model, the East
model, and constrained lattice gas models. We also show how large deviation
functions can be obtained from a Landau-like theory for dynamical fluctuations.
We discuss possibilities for similar dynamical phase-coexistence behaviour in
other systems with heterogeneous dynamics.Comment: 29 pages, 7 figs, final versio
Time dependence of breakdown in a global fiber-bundle model with continuous damage
A time-dependent global fiber-bundle model of fracture with continuous damage
is formulated in terms of a set of coupled non-linear differential equations. A
first integral of this set is analytically obtained. The time evolution of the
system is studied by applying a discrete probabilistic method. Several results
are discussed emphasizing their differences with the standard time-dependent
model. The results obtained show that with this simple model a variety of
experimental observations can be qualitatively reproduced.Comment: APS style, two columns, 4 figures. To appear in Phys. Rev.
Linear response theory and transient fluctuation theorems for diffusion processes: a backward point of view
On the basis of perturbed Kolmogorov backward equations and path integral
representation, we unify the derivations of the linear response theory and
transient fluctuation theorems for continuous diffusion processes from a
backward point of view. We find that a variety of transient fluctuation
theorems could be interpreted as a consequence of a generalized
Chapman-Kolmogorov equation, which intrinsically arises from the Markovian
characteristic of diffusion processes
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