# Tuning Feshbach resonance in cold atomic gases with inter-channel coupling

## TL;DR

This paper demonstrates how inter-channel coupling can be used to tune Feshbach resonances in cold atomic gases, providing new control over atomic interactions and affecting many-body phenomena like the BCS-BEC crossover.

## Contribution

It introduces a scheme to control Feshbach resonances via inter-channel dressing, applicable to alkaline-earth-like atoms, and explores its effects on many-body physics.

## Key findings

- Resonance position and bound-state energy depend on inter-channel coupling.
- Inter-channel coupling enables tuning of atomic interactions.
- Dressed Feshbach resonance significantly influences many-body processes.

## Abstract

We show that the essential properties of a Feshbach resonance in cold atomic gases can be tuned by dressing the atomic states in different scattering channels through inter-channel couplings. Such a scheme can be readily implemented in the orbital Feshbach resonance of alkaline-earth-like atoms by coupling hyperfine states in the clock-state manifolds. Using $^{173}$Yb atoms as an example, we find that both the resonance position and the two-body bound-state energy depend sensitively on the inter-channel coupling strength, which offers control parameters in tuning the inter-atomic interactions. We also demonstrate the dramatic impact of the dressed Feshbach resonance on many-body processes such as the polaron to molecule transition and the BCS-BEC crossover.