In the realm of energy research, understanding the behavior of particles in constrained environments can have significant implications for various technologies. Meitar Goldfarb and Stanislav Burov, researchers from the University of California, Berkeley, have delved into this area with their study on boundary-induced drift and negative mobility in constrained stochastic systems.
The researchers investigated the dynamics of particles that are confined by hard boundaries and subjected to random movements, a scenario commonly referred to as overdamped stochastic dynamics. They discovered that the combination of boundary geometry and anisotropic diffusion—where particles move more easily in one direction than another—can generate directed motion. This phenomenon occurs because particles reflect off the boundaries at an angle, creating a systematic drift parallel to the surface.
The local velocity resulting from this drift is determined by the diffusion tensor, which describes the particle’s movement, and the local boundary geometry. While this drift is local, it can accumulate over multiple boundary encounters, leading to macroscopic transport. To illustrate this, the researchers used a simple one-dimensional model consisting of two particles with different diffusion coefficients. They found that repeated collisions between these particles could result in sustained center-of-mass motion, including instances of absolute negative mobility under constant forcing. This means that the particles can move in the opposite direction to the applied force.
The practical applications of this research for the energy sector are manifold. For instance, understanding and controlling the directed motion of particles in constrained environments could enhance the efficiency of energy storage systems, such as batteries, by improving the transport of ions. Additionally, this knowledge could be applied to the development of more efficient catalytic processes, where the directed motion of particles could facilitate chemical reactions. Furthermore, the insights gained from this study could inform the design of microfluidic devices used in energy conversion and storage technologies.
The research was published in the journal Physical Review Letters, a prestigious publication in the field of physics. The findings contribute to our understanding of particle dynamics in constrained environments and open up new avenues for the development of innovative energy technologies.
This article is based on research available at arXiv.