Non-adiabatic pumping in an oscillating-piston model

TL;DR

This paper investigates a ring-based piston pump driven by AC, analyzing non-adiabatic effects and phase-space structures that influence particle transport, revealing deviations from classical adiabatic and Boltzmann models.

Contribution

It introduces a generalized Fermi-Ulam model with a finite-height piston on a ring, highlighting the layered phase-space structure and diabatic effects on transport.

Findings

Layered phase-space determines particle transport per cycle.

Diabatic contributions can cause counter-stirring effects.

Differences from adiabatic and Boltzmann models are significant.

Abstract

We consider the prototypical "piston pump" operating on a ring, where a circulating current is induced by means of an AC driving. This can be regarded as a generalized Fermi-Ulam model, incorporating a finite-height moving wall (piston) and non trivial topology (ring). The amount of particles transported per cycle is determined by a layered structure of phase-space. Each layer is characterized by a different drift velocity. We discuss the differences compared with the adiabatic and Boltzmann pictures, and highlight the significance of the "diabatic" contribution that might lead to a counter-stirring effect.