Generation of many-body Bell correlations with short-range interactions in analog and digital quantum simulators

TL;DR

This paper shows how short-range interactions in quantum simulators can produce many-body Bell correlations and spin-squeezed states, enabling quantum resource generation without all-to-all couplings.

Contribution

It introduces a method to generate many-body Bell correlations using short-range interactions in spin chain models, expanding capabilities of current quantum simulators.

Findings

Effective OAT nonlinearity from short-range interactions

Generation of spin-squeezed states and Bell correlations

Correlations can be read out with a single probe qubit

Abstract

The dynamical generation of quantum resources, such as many-body entanglement or Bell correlations, can be achieved via one-axis twisting (OAT) dynamics, which require all-to-all couplings. However, current digital and analog quantum simulation platforms natively provide short-range or power-law couplings that decay too quickly for this purpose. We demonstrate that two spin-$\tfrac12$ chain models -- a staggered nearest-neighbor XXX chain and a long-range XXZ chain -- develop an effective OAT nonlinearity when projected onto the symmetric sector. We show that these dynamics generate metrologically useful spin-squeezed states and Greenberger-Horne-Zeilinger coherences that ensure violation of many-body Bell inequalities. We confirm the accuracy of this mapping by comparing it to the exact dynamics and demonstrate that the generated correlations can be read out using a single probe qubit. The resulting dynamics can be simulated with analog and digital quantum simulators