Near Threshold Effects on Recombination and Vibrational Relaxation in Efimov Systems

Abstract

We investigate the energy dependence of inelastic processes in systems which possess Efimov states. We consider the three-body recombination rate K3 where three free atoms interact to produce an atom-dimer pair, and the relaxation rate K rel where an atom quenches a weakly bound state of a dimer near an Efimov resonance to more deeply bound levels. Using a model capturing the key features of the Efimov problem, we identify new energy regimes for K3, namely the NTR (Near Threshold Resonance) regime behavior E −2 for negative scattering lengths and the NTS (Near Threshold Suppression) regime behavior E 2 for positive scattering lengths. We also confirm a previously found oscillatory behavior of K3 at higher energy E. Finally, we find that K rel behaves as E −1 in the NTR regime.

Few-body physics in resonantly interacting ultracold quantum gases

“…In the unitarity regime, Efimov states lead to oscillations in the inelastic three-body rates as the energy changes, with the number of oscillations determined by the number of Efimov states for a given value of a [207,208] (see also Refs. [112] and [210]) .…”

“…Although equations (124)- (126) give a limiting value for the inelastic collision rates in the unitarity regime, they are only part of the story for attractive three-body systems. In the unitarity regime, Efimov states lead to oscillations in the inelastic three-body rates as the energy changes, with the number of oscillations determined by the number of Efimov states for a given value of a [207,208] (see also [112,210]).…”

Phase-amplitude formalism for ultranarrow shape resonances

“…The approach presented here could be adapted to shape resonances in low energy scattering [44], and to ultra-long-range Rydberg molecular potentials [45,46], and may also prove useful for analyzing threshold behavior [47,48] relevant to ultracold molecules [49,50], especially when near-threshold resonances exist [51][52][53][54]. Moreover, we are currently investigating the possibility of extending the phase-amplitude formalism to coupled-channel problems which would allow studies of Feshbach resonances [55,56].…”

Molecular hydrogen: a benchmark system for near threshold resonances in high partial waves

“…This high level of control over interactions can be realized using Feshbach resonances [13], or by orienting ultracold molecules [14,15]. In addition to investigations of degenerate quantum gases [16,17], such control also allows studies of exotic three-body Efimov states [18,19] or application to quantum information processing [20][21][22].…”