Propagation of guided cold atoms

TL;DR

This paper investigates how guided cold atoms propagate in different regimes, using hydrodynamic equations in the classical case and quantum models for bosons, aiming to enhance collision rates for quantum degeneracy.

Contribution

It introduces a formalism for classical guided atom beams and analyzes quantum propagation through constrictions, comparing collisionless and Thomas-Fermi regimes.

Findings

Hydrodynamic equations effectively describe classical beam propagation.

Constrictions and tilting increase collision rates in classical regimes.

Quantum analysis reveals distinct behaviors in collisionless and Thomas-Fermi regimes.

Abstract

In this article we focus on the propagation of a beam of particles guided by a transversely confining potential. We consider different regimes. In the classical regime, we describe the beam by means of a set of hydrodynamic-like equations. We apply this formalism in order to investigate two practical ways for increasing the collision rate: by using a constriction or by tilting the guide. A high enough collision rate is indeed the most crucial prerequisite for reaching the quantum degenerate regime by means of evaporative cooling. In the quantum regime, we study the propagation of bosonic atoms through a constriction in two opposite regimes: the collision-less one and the Thomas-Fermi one.