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, $R_1(t) \sim t^{1/3}$.Comment: Accepted for publication in PCCP on 24th May 201