# Interactions between non-resonant rf fields and atoms with strong spin-exchange collisions

## TL;DR

This paper investigates how non-resonant rf fields interact with atoms experiencing strong spin-exchange collisions, revealing new effects on atomic precession frequencies and gyromagnetic ratios, supported by experiments and theoretical models.

## Contribution

It uncovers a previously neglected narrow regime where spin-exchange collisions significantly alter rf field effects on atomic spins, with experimental validation and theoretical explanation.

## Key findings

- Atomic Larmor frequency exhibits a new dependence on rf parameters when spin-exchange rate is tuned.
- Strong spin-exchange modifies the position of the minimum gyromagnetic ratio point caused by rf photon dressing.
- Experimental results align with density matrix calculations and an underdamped oscillator model.

## Abstract

We study the interactions between oscillating non-resonant rf fields and atoms with strong spin-exchange collisions in the presence of a weak dc magnetic field. We find that the atomic Larmor precession frequency shows a new functional form to the rf field parameters when the spin-exchange collision rate is tuned. In the weak rf field amplitude regime, a strong modification of atomic Larmor frequency appears when the spin-exchange rate is comparable to the rf field frequency. This new effect has been neglected before due to its narrow observation window. We compare the experimental results with density matrix calculations, and explain the data by an underdamped oscillator model. When the rf field amplitude is large, there is a minimum atomic gyromagnetic ratio point due to the rf photon dressing, and we find that strong spin-exchange interactions modify the position of such a point.