Spin Squeezing with Itinerant Dipoles: A Case for Shallow Lattices

TL;DR

This paper demonstrates that shallow lattices with itinerant dipoles can generate significant spin squeezing, outperforming deep lattices even under realistic experimental conditions, due to SU(2) symmetry preserving correlations.

Contribution

It introduces a detailed analysis of spin squeezing in shallow lattices with itinerant fermionic dipoles, highlighting the advantages over deep lattices and the role of superexchange interactions.

Findings

Shallow lattices achieve over 5dB of squeezing, surpassing deep lattices by more than 3dB.

SU(2)-symmetric superexchange interactions protect collective correlations.

Optimal squeezing occurs at small repulsive off-site interactions, balancing squeezing magnitude and timing.

Abstract

Entangled spin squeezed states generated via dipolar interactions in lattice models provide unique opportunities for quantum enhanced sensing and are now within reach of current experiments. A critical question in this context is which parameter regimes offer the best prospects under realistic conditions. Light scattering in deep lattices can induce significant decoherence and strong Stark shifts, while shallow lattices face motional decoherence as a fundamental obstacle. Here we analyze the interplay between motion and spin squeezing in itinerant fermionic dipoles in one dimensional chains using exact matrix product state simulations. We demonstrate that shallow lattices can achieve more than 5dB of squeezing, outperforming deep lattices by up to more than 3dB, even in the presence of low filling, loss and decoherence. We relate this finding to SU(2)-symmetric superexchange interactions, which keep spins aligned and protect collective correlations. We show that the optimal regime is achieved for small repulsive off-site interactions, with a trade-off between maximal squeezing and optimal squeezing time.