# Collective tunnelling of strongly interacting cold atoms in a double well potential

## TL;DR

This paper investigates the collective tunnelling behavior of strongly interacting cold atoms in a double-well potential, revealing the mechanisms behind synchronized atom transfer and the effects of tunnelling initiation methods.

## Contribution

It provides a detailed analysis of the collective tunnelling mechanism, evaluates Rabi frequencies, and discusses the impact of tunnelling onset on oscillation behavior.

## Key findings

- Superimposed rapid oscillations result from cluster splitting at tunnelling onset.
- Gradual tunnelling initiation suppresses rapid oscillations.
- Strong interactions lead to collective atom transfer resembling single-particle dynamics.

## Abstract

It is known that under resonance conditions, a group of strongly interacting bosonic atoms, trapped in a double-well potential, mimics a single particle, performing Rabi oscillations between the wells. By implication, all atoms need to tunnel at roughly the same time, even though the Bose-Hubbard Hamiltonian accounts only for one-atom-at-a-time transfers. We analyse the mechanism of this collective behaviour, evaluate the Rabi frequencies in the process, and discuss the limitation of this simple picture. In particular, is is shown that the small rapid oscillations superimposed on the slow Rabi cycle, result from splitting the transferred cluster at the sudden onset of tunnelling, and disappear if tunnelling is turned on gradually.