Spin Squeezing with Magnetic Dipoles

TL;DR

This paper demonstrates how magnetic dipole interactions in neutral atoms can generate spin-squeezed states, enhancing quantum measurement precision, with potential applications in quantum metrology and studying long-range quantum magnetism.

Contribution

It introduces a novel method to produce spin squeezing using native magnetic dipole interactions in neutral atoms, extending quantum metrology capabilities.

Findings

Achieved 7.1 dB of metrologically useful spin squeezing.

Proposed atomic motion to protect coherence and improve squeezing.

Demonstrated applicability to various neutral atom systems.

Abstract

Entanglement can improve the measurement precision of quantum sensors beyond the shot noise limit. Neutral atoms, the basis of some of the most precise and accurate optical clocks and interferometers, do not naturally exhibit all-to-all interactions that are traditionally used to generate such entangled states. Instead, we take advantage of the magnetic dipole-dipole interaction native to most neutral atoms to realize spin-squeezed states. We achieve 7.1 dB of metrologically useful squeezing using the finite-range spin exchange interactions in an erbium quantum gas microscope. We further propose and demonstrate that introducing atomic motion protects the spin sector coherence at low fillings, significantly improving the achievable spin squeezing in a 2D dipolar system. This work's protocol can be implemented with most neutral atoms, opening the door to quantum-enhanced metrology in other itinerant dipolar systems, such as molecules or optical lattice clocks, and serves as a novel method for studying itinerant quantum magnetism with long-range interactions.