Radio-frequency association of molecules: the dressed state picture

TL;DR

This paper presents a theoretical model for rf-induced atom-molecule coupling using the dressed state picture, validated by experiments with ultracold chromium atoms, revealing the coupling strength dependence on Bessel functions.

Contribution

It introduces a novel theoretical framework linking rf coupling strength to Bessel functions and experimentally confirms this relationship in ultracold atom collisions.

Findings

Coupling strength proportional to the square of a Bessel function.

Experimental validation with ultracold chromium atoms.

Dependence on the ratio of Rabi frequency to rf frequency.

Abstract

We develop a theoretical model to describe the radio-frequency (rf) induced coupling of a pair of colliding atoms to a Feshbach molecule when a magnetic field arbitrarily far from the Feshbach resonance is modulated in time. We use the dressed atom picture, and show that the coupling strength in presence of rf is equal to the Feshbach coupling strength multiplied by the square of a Bessel function. The argument of this function is equal to the ratio of the atomic rf Rabi frequency to the rf frequency. We experimentally demonstrate this law by measuring the rate of rf-association of molecules using a Feshbach resonance in d-wave collisions between ultra-cold chromium atoms.