1,254 research outputs found
Stochastically perturbed flows: Delayed and interrupted evolution
We present analytical expressions for the time-dependent and stationary
probability distributions corresponding to a stochastically perturbed
one-dimensional flow with critical points, in two physically relevant
situations: delayed evolution, in which the flow alternates with a quiescent
state in which the variate remains frozen at its current value for random
intervals of time; and interrupted evolution, in which the variate is also
re-set in the quiescent state to a random value drawn from a fixed
distribution. In the former case, the effect of the delay upon the first
passage time statistics is analyzed. In the latter case, the conditions under
which an extended stationary distribution can exist as a consequence of the
competition between an attractor in the flow and the random re-setting are
examined. We elucidate the role of the normalization condition in eliminating
the singularities arising from the unstable critical points of the flow, and
present a number of representative examples. A simple formula is obtained for
the stationary distribution and interpreted physically. A similar
interpretation is also given for the known formula for the stationary
distribution in a full-fledged dichotomous flow.Comment: 27 pages; no figures. Submitted to Stochastics and Dynamic
Jarzynski equality for the Jepsen gas
We illustrate the Jarzynski equality on the exactly solvable model of a
one-dimensional ideal gas in uniform expansion or compression. The analytical
results for the probability density of the work performed by the gas
are compared with the results of molecular dynamics simulations for a
two-dimensional dilute gas of hard spheres.Comment: 7 pages, 4 figures, submitted to Europhys. Let
Stochastic Stokes' drift of a flexible dumbbell
We consider the stochastic Stokes drift of a flexible dumbbell. The dumbbell
consists of two isotropic Brownian particles connected by a linear spring with
zero natural length, and is advected by a sinusoidal wave. We find an
asymptotic approximation for the Stokes drift in the limit of a weak wave, and
find good agreement with the results of a Monte Carlo simulation. We show that
it is possible to use this effect to sort particles by their flexibility even
when all the particles have the same diffusivity.Comment: 12 pages, 1 figur
Critical Behaviour of Non-Equilibrium Phase Transitions to Magnetically Ordered States
We describe non-equilibrium phase transitions in arrays of dynamical systems
with cubic nonlinearity driven by multiplicative Gaussian white noise.
Depending on the sign of the spatial coupling we observe transitions to
ferromagnetic or antiferromagnetic ordered states. We discuss the phase
diagram, the order of the transitions, and the critical behaviour. For global
coupling we show analytically that the critical exponent of the magnetization
exhibits a transition from the value 1/2 to a non-universal behaviour depending
on the ratio of noise strength to the magnitude of the spatial coupling.Comment: 4 pages, 5 figure
Efficiency at maximum power: An analytically solvable model for stochastic heat engines
We study a class of cyclic Brownian heat engines in the framework of
finite-time thermodynamics. For infinitely long cycle times, the engine works
at the Carnot efficiency limit producing, however, zero power. For the
efficiency at maximum power, we find a universal expression, different from the
endoreversible Curzon-Ahlborn efficiency. Our results are illustrated with a
simple one-dimensional engine working in and with a time-dependent harmonic
potential.Comment: 6 pages, 3 figure
Reconstructing Colonization Dynamics of the Human Parasite Schistosoma mansoni following Anthropogenic Environmental Changes in Northwest Senegal
© 2015 Van den Broeck et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
- …