Generating multipartite spin states with fermionic atoms in a driven optical lattice

TL;DR

This paper presents a protocol for creating GHZ entangled states with ultracold fermions in optical lattices, enabling quantum-enhanced metrology without complex site-resolved control.

Contribution

It introduces a robust, scalable method to generate multipartite entanglement using global operations and trap dynamics, advancing quantum sensor technology.

Findings

Protocol successfully generates GHZ states in 3D optical lattices.

Method is robust to laser phase drift and does not require site-resolved control.

Potential to enhance sensitivity of optical lattice clocks beyond standard quantum limit.

Abstract

We propose a protocol for generating generalized GHZ states using ultracold fermions in 3D optical lattices or optical tweezer arrays. The protocol uses the interplay between laser driving, onsite interactions and external trapping confinement to enforce energetic spin- and position-dependent constraints on the atomic motion. These constraints allow us to transform a local superposition into a GHZ state through a stepwise protocol that flips one site at a time. The protocol requires no site-resolved drives or spin-dependent potentials, exhibits robustness to slow global laser phase drift, and naturally makes use of the harmonic trap that would normally cause difficulties for entanglement-generating protocols in optical lattices. We also discuss an improved protocol that can compensate for holes in the loadout at the cost of increased generation time. The state can immediately be used for quantum-enhanced metrology in 3D optical lattice clocks, opening a window to push the sensitivity of state-of-the-art sensors beyond the standard quantum limit.