Quantum kinetic theory model of a continuous atom laser

TL;DR

This paper models a continuous atom laser using quantum kinetic theory, exploring feasible operational limits, and suggests that certain MOT sources can produce substantial condensates with narrow linewidths and reasonable flux.

Contribution

It introduces a quantum kinetic model for a continuous atom laser and identifies feasible source conditions and limitations for its practical realization.

Findings

High-temperature sources can produce substantial condensates.

Three-body loss limits the phase-space flux in low-flux sources.

Certain double-MOT sources can achieve narrow linewidth atom lasers.

Abstract

We investigate the feasible limits for realising a continuously evaporated atom laser with high-temperature sources. A plausible scheme for realising a truly continuous atom laser is to outcouple atoms from a partially condensed Bose gas, whilst continuously reloading the system with non-condensed thermal atoms and performing evaporative cooling. Here we use quantum kinetic theory to model this system and estimate feasible limits for the operation of such a scheme. For sufficiently high temperatures, the figure of merit for the source is shown to be the phase-space flux. The dominant process limiting the usage of sources with low phase-space flux is the three-body loss of the condensed gas. We conclude that certain double-magneto-optical trap (MOT) sources may produce substantial mean condensate numbers through continuous evaporation, and provide an atom laser source with a narrow linewidth and reasonable flux.