Measurement-based entanglement of noninteracting bosonic atoms

TL;DR

This paper demonstrates a method to generate spin-entangled states of two neutral atoms using measurement-based postselection and Hong-Ou-Mandel interference, bypassing the need for direct atom-atom interactions.

Contribution

It introduces a novel approach to entangle neutral atoms via measurement and interference, analogous to photon polarization entanglement techniques.

Findings

Achieved a postselected fidelity of 0.62 for the spin-singlet state.

Verified entanglement through measurement and analysis.

Showed potential for photon-based protocols to create complex atomic states.

Abstract

We demonstrate the ability to extract a spin-entangled state of two neutral atoms via postselection based on a measurement of their spatial configuration. Typically, entangled states of neutral atoms are engineered via atom-atom interactions. In contrast, in our work we use Hong-Ou-Mandel interference to postselect a spin-singlet state after overlapping two atoms in distinct spin states on an effective beam splitter. We verify the presence of entanglement and determine a bound on the postselected fidelity of a spin-singlet state of $\left(0.62 \pm 0.03\right)$. The experiment has direct analogy to creating polarization entanglement with single photons and hence demonstrates the potential to use protocols developed for photons to create complex quantum states with noninteracting atoms.