Many-body collisional dynamics of impurities injected into a double-well trapped Bose-Einstein condensate

TL;DR

This paper investigates the complex many-body dynamics of impurities interacting with a bosonic medium in a double-well trap, revealing how different interaction strengths lead to varied tunneling, pinning, and entanglement behaviors.

Contribution

It provides a detailed classification of impurity dynamics in a double-well Bose-Einstein condensate based on interaction strength, including the extension to two impurities.

Findings

Strong attraction binds impurity to the bath.

Intermediate attraction causes effective tunneling.

Strong repulsion leads to impurity pinning and reflection.

Abstract

We unravel the many-body dynamics of a harmonically trapped impurity colliding with a bosonic medium confined in a double-well upon quenching the initially displaced harmonic trap to the center of the double-well. We reveal that the emerging correlation dynamics crucially depends on the impurity-medium interaction strength allowing for a classification into different dynamical response regimes. For strong attractive impurity-medium couplings the impurity is bound to the bosonic bath, while for intermediate attractions it undergoes an effective tunneling. In the case of weak attractive or repulsive couplings the impurity penetrates the bosonic bath and performs a dissipative oscillatory motion. Further increasing the impurity-bath repulsion results in the pinning of the impurity between the density peaks of the bosonic medium, a phenomenon that is associated with a strong impurity-medium entanglement. For strong repulsions the impurity is totally reflected by the bosonic medium. To unravel the underlying microscopic excitation processes accompanying the dynamics we employ an effective potential picture. We extend our results to the case of two bosonic impurities and demonstrate the existence of a qualitatively similar impurity dynamics.