In: Physical Review E, 2020, vol. 102, no. 4, p. 042140
The Barker-Henderson perturbation theory is a bedrock of liquid-state physics, providing quantitative predictions for the bulk thermodynamic properties of realistic model systems. However, this successful method has not been exploited for the study of inhomogeneous systems. We develop and implement a first-principles “Barker- Henderson density functional,” thus providing a robust and...
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In: New Journal of Physics, 2020, vol. 22, no. 9, p. 093057
We study the motion of a Brownian particle subjected to Lorentz force due to an external magnetic field. Each spatial degree of freedom of the particle is coupled to a different thermostat. We show that the magnetic field results in correlation between different velocity components in the stationary state. Integrating the velocity autocorrelation matrix, we obtain the diffusion matrix that...
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In: Physical Review E, 2020, vol. 101, no. 1, p. 012120
The Fokker-Planck equation provides a complete statistical description of a particle undergoing random motion in a solvent. In the presence of Lorentz force due to an external magnetic field, the Fokker-Planck equation picks up a tensorial coefficient, which reflects the anisotropy of the particle's motion. This tensor, however, cannot be interpreted as a diffusion tensor; there are...
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In: Physical Review E, 2019, vol. 100, no. 1, p. 012601
Activity significantly enhances the escape rate of a Brownian particle over a potential barrier. Whereas constant activity has been extensively studied in the past, little is known about the effect of time-dependent activity on the escape rate of the particle. In this paper, we study the escape problem for a Brownian particle that is transiently active; the activity decreases rapidly during...
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In: Journal of Statistical Mechanics: Theory and Experiment, 2019, vol. 2019, no. 6, p. 063203
We study the stochastic motion of a particle subject to spatially varying Lorentz force in the small-mass limit. The limiting procedure yields an additional drift term in the overdamped equation that cannot be obtained by simply setting mass to zero in the velocity Langevin equation. We show that whereas the overdamped equation of motion accurately captures the position statistics of the...
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In: Soft Matter, 2019, vol. 15, no. 6, p. 1319–1326
We study the phase transition dynamics of a fluid system in which the particles diffuse anisotropically in space. The motivation to study such a situation is provided by systems of interacting magnetic colloidal particles subject to the Lorentz force. The Smoluchowski equation for the many-particle probability distribution then acquires an anisotropic diffusion tensor. We show that in...
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In: The Journal of Chemical Physics, 2018, vol. 148, no. 19, p. 194116
In a theoretical and simulation study, active Brownian particles (ABPs) in three- dimensional bulk systems are exposed to time-varying sinusoidal activity waves that are running through the system. A linear response (Green-Kubo) formalism is applied to derive fully analytical expressions for the torque-free polarization profiles of non- interacting particles. The activity waves induce fluxes...
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In: Physical Review E, 2018, vol. 98, no. 1, p. 012601
Using overdamped Brownian dynamics simulations we investigate the isotropic- nematic (IN) transition of self-propelled rods in three spatial dimensions. For two well- known model systems (Gay-Berne potential and hard spherocylinders) we find that turning on activity moves to higher densities the phase boundary separating an isotropic phase from a (nonpolar) nematic phase. This active IN phase...
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In: Molecular Physics, 2018, vol. 116, no. 4, p. 460–464
We investigate the mean first passage time of an active Brownian particle in one dimension using numerical simulations. The activity in one dimension is modelled as a two state model; the particle moves with a constant propulsion strength but its orientation switches from one state to other as in a random telegraphic process. We study the influence of a finite resetting rate r on the mean...
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In: Physical Review E, 2018, vol. 97, no. 1, p. 012601
We consider the steady-state behavior of pairs of active particles having different persistence times and diffusivities. To this purpose we employ the active Ornstein- Uhlenbeck model, where the particles are driven by colored noises with exponential correlation functions whose intensities and correlation times vary from species to species. By extending Fox's theory to many components, we...
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