Generation and Detection of Atomic Spin Entanglement in Optical Lattices

TL;DR

This paper demonstrates the generation, manipulation, and detection of atomic spin entanglement in an optical lattice, achieving high fidelity and Bell inequality violation, advancing scalable quantum computing with ultracold atoms.

Contribution

It introduces a method to generate and detect atomic spin entanglement in an optical superlattice with high fidelity and demonstrates Bell inequality violation.

Findings

Spin entanglement fidelity lower bound of 0.79

Bell inequality violation with S=2.21

High-fidelity coherent manipulation of atomic spins

Abstract

Ultracold atoms in optical lattices offer a great promise to generate entangled states for scalable quantum information processing owing to the inherited long coherence time and controllability over a large number of particles. We report on the generation, manipulation and detection of atomic spin entanglement in an optical superlattice. Employing a spin-dependent superlattice, atomic spins in the left or right sites can be individually addressed and coherently manipulated by microwave pulses with near unitary fidelities. Spin entanglement of the two atoms in the double wells of the superlattice is generated via dynamical evolution governed by spin superexchange. By observing collisional atom loss with in-situ absorption imaging we measure spin correlations of atoms inside the double wells and obtain the lower boundary of entanglement fidelity as $0.79\pm0.06$, and the violation of a Bell's inequality with $S=2.21\pm 0.08$. The above results represent an essential step towards scalable quantum computation with ultracold atoms in optical lattices.