# Non-adiabatic molecular association in thermal gases driven by radio-frequency pulses

## TL;DR

This paper investigates how radio-frequency pulses induce non-adiabatic molecular association in thermal gases, revealing interference fringes caused by St"uckelberg phase accumulation that are robust across various temperatures.

## Contribution

It introduces a detailed analysis of dynamical interference effects in molecular association driven by RF pulses, accounting for pulse envelope effects and thermal averaging.

## Key findings

- Interference fringes in molecular conversion efficiency increase with pulse length.
- Fringes are robust under thermal averaging across a wide temperature range.
- St"uckelberg phase accumulation explains the observed interference phenomena.

## Abstract

The molecular association process in a thermal gas of $^{85}$Rb is investigated where the effects of the envelope of the radio-frequency field are taken into account. For experimentally relevant parameters our analysis shows that with increasing pulse length the corresponding molecular conversion efficiency exhibits low-frequency interference fringes which are robust under thermal averaging over a wide range of temperatures. This dynamical interference phenomenon is attributed to St\"uckelberg phase accumulation between the low-energy continuum states and the dressed molecular state which exhibits a shift proportional to the envelope of the radio-frequency pulse intensity.