Casimir force driven ratchets

TL;DR

This paper investigates how the Casimir force between patterned metal surfaces can induce directed lateral motion through a ratchet effect, considering non-linear, chaotic, and noise-stable dynamics.

Contribution

It introduces a novel mechanism where Casimir forces generate ratchet-driven motion in patterned surfaces, including analysis of inertia, chaos, and stability.

Findings

Multiple velocity reversals as a function of parameters

Chaotic dynamics influence transport behavior

Transport remains stable under weak noise

Abstract

We explore the non-linear dynamics of two parallel periodically patterned metal surfaces that are coupled by the zero-point fluctuations of the electromagnetic field between them. The resulting Casimir force generates for asymmetric patterns with a time-periodically driven surface-to-surface distance a ratchet effect, allowing for directed lateral motion of the surfaces in sizeable parameter ranges. It is crucial to take into account inertia effects and hence chaotic dynamics which are described by Langevin dynamics. Multiple velocity reversals occur as a function of driving, mean surface distance, and effective damping. These transport properties are shown to be stable against weak ambient noise.