Ballistic atom pumps

TL;DR

This paper investigates a chaotic system with oscillating barriers connecting two reservoirs, demonstrating conditions for unidirectional particle pumping and analyzing classical, semiclassical, and quantum behaviors.

Contribution

It introduces a method to create a particle diode and explores how symmetric barriers can produce net transport under finite energy conditions, linking classical and quantum insights.

Findings

A particle diode can be formed under specific conditions.

Symmetric barriers do not produce net pumping for all energies.

Quantum behavior aligns with classical and semiclassical analysis when understood together.

Abstract

We examine a classically-chaotic system consisting of two reservoirs of particles connected by a channel containing oscillating potential-energy barriers. We investigate whether such a system can preferentially pump particles from one reservoir to the other, a process often called "quantum pumping." We show how to make a "particle diode" which under specified conditions permits net particle pumping in only one direction. Then we examine systems having symmetric barriers. We find that if all initial particle energies are considered, a system with symmetric barriers cannot preferentially pump particles. However, if only finite initial energy bands are considered, the system can create net particle transport in either direction. We study the system classically, semiclassically, and quantum mechanically, and find that the quantum description cannot be fully understood without the insight gained from classical and semiclassical analysis.