Criticality and Spin Squeezing in the Rotational Dynamics of a BEC on a Ring Lattice

TL;DR

This paper investigates the critical behavior and spin squeezing phenomena in a Bose-Einstein condensate on a ring lattice, demonstrating enhanced rotation sensitivity and proposing a quantum interferometric scheme leveraging spin squeezing.

Contribution

It introduces a novel analysis of criticality-induced spin squeezing in BECs on ring lattices and proposes a Ramsey interferometry method to improve rotation measurement precision.

Findings

Criticality enhances rotation sensitivity in BEC dynamics.

Significant quantum fluctuations occur near the critical point.

Spin squeezing can be used to suppress fluctuations in rotation sensing.

Abstract

We examine the dynamics of circulating modes of a Bose-Einstein condensate confined in toroidal lattice. Nonlinearity due to interactions leads to criticality that separates oscillatory and self-trapped phases among counter-propagating modes which however share the same physical space. In the mean-field limit, the criticality is found to substantially enhance sensitivity to rotation of the system. Analysis of the quantum dynamics reveals the fluctuations near criticality are significant, that we explain using spin-squeezing formalism visualized on a Bloch sphere. We utilize the squeezing to propose a Ramsey interferometric scheme that suppresses fluctuation in the relevant quadrature sensitive to rotation.