# Quantum correlations protection through spin self-rephasing in 1-D Bose gas

## TL;DR

This paper presents a quantum mechanical simulation demonstrating how spin self-rephasing in a 1-D Bose gas can counteract magnetic field inhomogeneity, enhancing coherence and spin squeezing.

## Contribution

It provides the first ab initio numerical model of spin self-rephasing in a quantum regime, analyzing effects on entangled and spin squeezed states.

## Key findings

- Spin self-rephasing can significantly extend coherence time.
- Interactions and magnetic inhomogeneity jointly influence spin dynamics.
- Quantum simulations match experimental observations of coherence enhancement.

## Abstract

System consisting of a number of trapped atoms evolving under the influence of external inhomogenous magnetic field undergoes spin dephasing: classically, since each atom feels different field along its trajectory, the spin rotation rates differ; as a result the average spin decays. In a quantum mechanical context this corresponds to entanglement of spin and spatial degrees of freedom and nontrivial internal spin dynamics. The spin dephasing can be prevented by tuning the interaction between the atoms. This phenomenon, called spin self-rephasing, has been observed experimentally and can increase the coherence time by a large factor. While such systems have been studied from a semiclassical point of view, a quantum mechanical description is limited, especially in the case of entangled states. In this work we provide a numerical simulation of an ab initio model and provide realistic examples of spin self-rephasing used to counteract the effect of inhomogenous magnetic field. We analyze in particular the joint effect of magnetic field inhomogeneity and interactions on the coherent and spin squeezed states evolution.