Near Threshold Effects on Recombination and Vibrational Relaxation in Efimov Systems

TL;DR

This paper explores how near-threshold energies influence recombination and vibrational relaxation in Efimov systems, revealing new energy regimes and behaviors for these inelastic processes.

Contribution

It introduces a model that identifies new energy regimes (NTR and NTS) and characterizes their effects on inelastic rates near Efimov states.

Findings

Recombination rate $K_3$ exhibits $E^{-2}$ behavior in NTR regime for negative scattering lengths.

Relaxation rate $K_{rel}$ behaves as $E^{-1}$ in the NTR regime.

Confirmed oscillatory behavior of $K_3$ at higher energies.

Abstract

We investigate the energy dependence of inelastic processes in systems which possess Efimov states. We consider the three-body recombination rate $K_3$ where three free atoms interact to produce an atom--dimer pair, and the relaxation rate $K_{\rm rel}$ 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 $K_3$, 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 $K_3$ at higher energy $E$. Finally, we find that $K_{\rm rel}$ behaves as $E^{-1}$ in the NTR regime.