An entangling atomtronic beamsplitter

TL;DR

This paper proposes a three-well Bose-Hubbard model to generate and analyze spatially separated entangled atomic samples, demonstrating entanglement dynamics and methods for preservation, with potential applications in quantum non-locality tests.

Contribution

It introduces a novel three-well atomtronic system for creating and controlling entanglement between spatially separated atomic samples, analyzing its dynamics and robustness.

Findings

Entanglement oscillates with well occupations over time.

Violations of Hillery-Zubairy inequality occur only with initial Fock states.

Collisional nonlinearity degrades entanglement signals.

Abstract

We propose and analyse the use of a three-well Bose-Hubbard model for the creation of two spatially separated entangled atomic samples. Our three wells are in a linear configuration, with all atoms initially in the middle well, which gives some spatial separation of the two end wells. The evolution from the initial quantum state allows for the development of entanglement between the atomic modes in the two end wells. Using inseparability criteria developed by Hillery and Zubairy, we show how the detected entanglement is time dependent, oscillating with the well occupations. We suggest and analyse a method for preserving the entanglement by turning off the different interactions when it reaches its first maximum. We analyse the system with both Fock and coherent initial states, showing that the violations of the Hillery-Zubairy inequality exist only for initial Fock states and that the collisional nonlinearity degrades them. This system is an early step towards producing entangled atomic samples that can be spatially separated and thus close the locality loophole in tests of non-local quantum correlations.