2,619 research outputs found
Nonequilibrium Work distributions for a trapped Brownian particle in a time dependent magnetic field
We study the dynamics of a trapped, charged Brownian particle in presence of
a time dependent magnetic field. We calculate work distributions for different
time dependent protocols. In our problem thermodynamic work is related to
variation of vector potential with time as opposed to the earlier studies where
the work is related to time variation of the potentials which depends only on
the coordinates of the particle. Using Jarzynski identity and Crook's equality
we show that the free energy of the particle is independent of the magnetic
field, thus complementing the Bohr-van Leeuwen theorem. We also show that our
system exhibits a parametric resonance in certain parameter space.Comment: 4 pages and 5 figure
Entropy production theorems and some consequences
The total entropy production fluctuations are studied in some exactly
solvable models. For these systems, the detailed fluctuation theorem holds even
in the transient state, provided initially the system is prepared in thermal
equilibrium. The nature of entropy production during the relaxation of a system
to equilibrium is analyzed. The averaged entropy production over a finite time
interval gives a better bound for the average work performed on the system than
that obtained from the well known Jarzynski equality. Moreover, the average
entropy production as a quantifier for information theoretic nature of
irreversibility for finite time nonequilibrium processes is discussed.Comment: 12 pages, 3 figure
Particles with selective wetting affect spinodal decomposition microstructures
We have used mesoscale simulations to study the effect of immobile particles
on microstructure formation during spinodal decomposition in ternary mixtures
such as polymer blends. Specifically, we have explored a regime of
interparticle spacings (which are a few times the characteristic spinodal
length scale) in which we might expect interesting new effects arising from
interactions among wetting, spinodal decomposition and coarsening. In this
paper, we report three new effects for systems in which the particle phase has
a strong preference for being wetted by one of the components (say, A). In the
presence of particles, microstructures are not bicontinuous in a symmetric
mixture. An asymmetric mixture, on the other hand, first forms a
non-bicontinuous microstructure which then evolves into a bicontinuous one at
intermediate times. Moreover, while wetting of the particle phase by the
preferred component (A) creates alternating A-rich and B-rich layers around the
particles, curvature-driven coarsening leads to shrinking and disappearance of
the first A-rich layer, leaving a layer of the non-preferred component in
contact with the particle. At late simulation times, domains of the matrix
components coarsen following the Lifshitz-Slyozov-Wagner law, .Comment: Accepted for publication in PCCP on 24th May 201
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