2,039 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
Stochastic thermodynamics for kinetic equations
Stochastic thermodynamics is formulated for variables that are odd under time
reversal. The invariance under spatial rotation of the collision rates due to
the isotropy of the heat bath is shown to be a crucial ingredient. An
alternative detailed fluctuation theorem is derived, expressed solely in terms
of forward statistics. It is illustrated for a linear kinetic equation with
kangaroo rates
Stochastic energetics of a Brownian motor and refrigerator driven by non-uniform temperature
The energetics of a Brownian heat engine and heat pump driven by position
dependent temperature, known as the B\"uttiker-Landauer heat engine and heat
pump, is investigated by numerical simulations of the inertial Langevin
equation. We identify parameter values for optimal performance of the heat
engine and heat pump. Our results qualitatively differ from approaches based on
the overdamped model. The behavior of the heat engine and heat pump, in the
linear response regime is examined under finite time conditions and we find
that the efficiency is lower than that of an endoreversible engine working
under the same condition. Finally, we investigate the role of different
potential and temperature profiles to enhance the efficiency of the system. Our
simulations show that optimizing the potential and temperature profile leads
only to a marginal enhancement of the system performance due to the large
entropy production via the Brownian particle's kinetic energy.Comment: 14 pages, 15 figures (latest version with modified figures and text
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
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