Brownian Asymmetric Simple Exclusion Process

6 Sept 2018, 15:00
3h

Speaker

Dominik Lips (Universität Osnabrück, Germany)

Description

We present a model of a Brownian asymmetric simple exclusion process (BASEP) with underdamped Brownian Dynamics, which is an extension on the well-known asymmetric simple exclusion process (ASEP) defined on a discrete lattice. In the BASEP, particles of size $\sigma$ with hardcore interaction are driven by a constant drag force through a one-dimensional cosine potential with period $\lambda$. The amplitude of the cosine potential is much larger than $k_{\rm\scriptscriptstyle B} T$, leading to an effective hopping motion of particles between potential wells. Under periodic boundary conditions, the system reaches a non-equilibrium steady-state (NESS) with a constant particle current. In general, the character of these NESS is strikingly different from the one in the ASEP. Compared to the particle current in a system of non-interacting particles, we observe an enhancement for small $\sigma/\lambda$ ratios, caused by a barrier reduction effect arising from multi-occupation of potential wells. Larger ratios lead to a suppression of the current because of strong blocking effects. Surprisingly, an exchange-symmetry effect leads to a current-density relation identical to that of non-interacting particles for the commensurable length $\sigma=\lambda$. A current-density relation similar to the ASEP is obtained only for a limited parameter regime. The rich behavior of the current-density relation is reflected in non-equilibrium phase-diagrams for open-systems, which can exhibit up to five phases. The topology of these phase diagrams changes with varying $\sigma/\lambda$ ratio. We furthermore discuss transition times and splitting probabilities for a tagged particle in the BASEP. These quantities exhibit a remarkable asymmetry, which we relate to the collective particle motion in the NESS.

Primary author

Dominik Lips (Universität Osnabrück, Germany)

Co-authors

Dr Artem Ryabov (Charles University) Prof. Philipp Maass (Universität Osnabrück, Germany)

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