Effective Atom–Molecule Conversions Using Radio Frequency Fields

Abstract

The present study is inspired by the Wieman group experiment [Phys. Rev. Lett. 2005, 95, 190404], in which they use a slow modulated magnetic field to effectively transfer rubidium atoms into cold molecules near a Feshbach resonance. We develop a time-dependent collision theory based on two channel model potentials to study the atom-molecule population transfer induced by a single-color radio frequency field in an ultracold Rb gas. Wave-packet dynamical simulations allow an investigation of both bound-bound transitions and free-bound transitions. The effects of temperature, detuning and the RF amplitude on the population transfer are discussed in detail. Some of our simulations suggest that oscillatory atom-molecule conversion could originate from the long coherence time of the wave packet. This coherence time is unusually long in ultracold gases because the collision energy is typically quite well-defined.

Nonadiabatic Molecular Association in Thermal Gases Driven by Radio-Frequency Pulses

“…Techniques involving radio-frequency (RF) magnetic fields are of exceptional importance since they are highly adjustable in experiments [4,5]. Indeed, the additional magnetic RF field modulation enables the investigation of cold molecule formation [6][7][8] or heteronuclear association/dissociation processes in a microgravity environment [9], association of Efimov trimers [10][11][12][13] or manipulation of Feshbach collisions [14][15][16]. Beyond cold physics, external fields are also used in ultrafast physics where short laser pulses probe photoionization processes [17].…”