Engineering impurity Bell states through coupling with a quantum bath

TL;DR

This paper proposes a method to generate Bell states in ultra-cold atomic gases by controlling impurity interactions via Feshbach resonances, using a bosonic bath to mediate entanglement between impurities in a one-dimensional trap.

Contribution

It demonstrates how to create impurity Bell states through bath-mediated interactions and explores how bath properties influence entanglement in a cold atom system.

Findings

Impurities can form spatially entangled bipolaron states due to bath-mediated interactions.

Manipulating bath size, mass, and intraspecies interactions can optimize Bell state creation.

Inter-species interactions are crucial but can also inhibit correlations depending on system parameters.

Abstract

We theoretically demonstrate the feasibility of creating Bell states in multi-component ultra-cold atomic gases by solely using the ability to control the inter-particle interactions via Feshbach resonances. For this we consider two distinguishable impurities immersed in an atomic background cloud of a few bosons, with the entire system being confined in a one-dimensional harmonic trap. By analyzing the numerically obtained ground states we demonstrate that the two impurities can form spatially entangled bipolaron states due to mediated interactions from the bosonic bath. Our analysis is based on calculating the correlations between the two impurities in a two-mode basis, which is experimentally accessible by measuring the particles positions in the left or right sides of the trap. While interspecies interactions are crucial in order to create the strongly entangled impurity states, it can also inhibit correlations depending on the ordering of the impurities and three-body impurity-bath correlations. We show how these drawbacks can be mitigated by manipulating the properties of the bath, namely its size, mass and intraspecies interactions, allowing to create impurity Bell states over a wide range of impurity-impurity interactions.