3,268 research outputs found
Active Brownian particles: Entropy production and fluctuation-response
Within the Rayleigh-Helmholtz model of active Brownian particles activity is
due to a non-linear velocity dependent force. In the presence of an external
trapping potential or a constant force, the steady state of the system breaks
detailed balance producing a net entropy. Using molecular dynamics simulations,
we obtain the probability distributions of entropy production in these steady
states. The distribution functions obey detailed fluctuation theorem for
entropy production. Using simulation results, we further show that the steady
state response function obeys a modified fluctuation-dissipation relation.Comment: 8 pages, 6 figures; version accepted for publication in Phys. Rev.
The Symmetric Algebra for Certain Monomial Curves
In this article we compute a minimal Groebner basis for the symmetric algebra
for certain affine Monomial Curves, as an R-module.
Keywords: Monomial Curves, Groebner Basis, Symmetric Algebra. Mathematics
Subject Classification 2000: 13P10, 13A30
Stochastic models of classical particle pumps : Density dependence of directed current
We present and compare different versions of a simple particle pump-model
that describes average directed current of repulsively interacting particles in
a narrow channel, due to time-varying local potentials. We analyze the model on
discrete lattice with particle exclusion, using three choices of
potential-dependent hopping rates that obey microscopic reversibility. Treating
the strength of the external potential as a small parameter with respect to
thermal energy, we present a perturbative calculation to obtain the expression
for average directed current. This depends on driving frequency, phase, and
particle density. The directed current vanishes as density goes to zero or
close packing. For two choices of hopping rates, it reaches maximum at
intermediate densities, while for a third choice, it shows a curious current
reversal with increasing density. This can be interpreted in terms of a
particle-hole symmetry. Stochastic simulations of the model show good agreement
with our analytic predictions.Comment: 9 pages, 1 figure: Based on invited talk delivered by the author at
StatPhys-Kolkata VIII, Kolkata (India), December, 201
- …