Atomic-Molecular Condensates with Large Positive Scattering Length

TL;DR

This paper investigates the properties of atomic-molecular Bose-Einstein condensates with large positive scattering lengths, revealing universal behavior and optimal conditions for stability, along with insights into inelastic processes and monitoring techniques.

Contribution

It introduces a universal energy density functional for amBECs in the large positive scattering length regime and identifies conditions for their stability and non-destructive monitoring.

Findings

Universal energy density functional describes amBEC properties.

Optimal stability occurs without shallow trimers and with negative atom-dimer scattering length.

Inelastic processes allow non-destructive monitoring of the condensate.

Abstract

We show that in the limit of large and positive atom--atom scattering length the properties of an atomic--molecular Bose--Einstein Condensate (amBEC) are determined by an universal energy density functional (EDF). We find that the optimal conditions for the formation of a stable amBEC are in the regime where there are no shallow trimers and the atom--dimer scattering length is negative and comparable in magnitude with the atom--atom scattering length. At temperatures lower than $T_c$ the chemical potentials for the atoms and molecules can be specified independently. Besides three--body recombinations processes into dimers of large size, inelastic processes involving the formation of deeply bound small size molecular states are possible. These inelastic processes do not lead to an efficient heating of the amBEC and can be used for its mostly non--destructive monitoring.