Long-lived complexes and signatures of chaos in ultracold K2+Rb collisions

TL;DR

This paper reports on the microsecond lifetimes of ultracold K2+Rb collision complexes, analyzes their resonance signatures for quantum chaos, and compares quantum scattering results with a density-of-states model.

Contribution

It provides the first detailed quantum-scattering calculations of complex lifetimes and chaos signatures in ultracold K2+Rb collisions, linking resonance properties to quantum chaos.

Findings

Complex lifetimes are in the microsecond range.

Resonance positions follow Wigner-Dyson distribution.

Resonance widths follow Porter-Thomas distribution.

Abstract

Lifetimes of complexes formed during ultracold collisions are of current experimental interest as a possible cause of trap loss in ultracold gases of alkali-dimers. Microsecond lifetimes for complexes formed during ultracold elastic collisions of K2 with Rb are reported, from numerically-exact quantum-scattering calculations. The reported lifetimes are compared with those calculated using a simple density-of-states approach, which are shown to be reasonable. Long-lived complexes correspond to narrow scattering resonances which we examine for the statistical signatures of quantum chaos, finding that the positions and widths of the resonances follow the Wigner-Dyson and Porter-Thomas distributions respectively.