Thermally-robust spin correlations between two 85Rb atoms in an optical microtrap

TL;DR

This study demonstrates thermally-robust spin correlations between two individually trapped 85Rb atoms, revealing strong pair correlations and relaxation dynamics, advancing controlled quantum system investigations.

Contribution

It introduces a method to assemble and study two-atom spin dynamics in optical tweezers, highlighting thermal robustness and detailed correlation measurements.

Findings

Strong pair correlations persist over seconds

Number fluctuations are below quantum shot noise

Spin populations match theoretical predictions

Abstract

The complex collisional properties of atoms fundamentally limit investigations into a range of processes in many-atom ensembles. In contrast, the bottom-up assembly of few- and many-body systems from individual atoms offers a controlled approach to isolating and studying such collisional processes. Here, we use optical tweezers to individually assemble pairs of trapped $^{85}$Rb atoms, and study the spin dynamics of the two-body system in a thermal state. The spin-2 atoms show strong pair correlation between magnetic sublevels on timescales exceeding one second, with measured relative number fluctuations $11.9\pm0.3$ dB below quantum shot noise, limited only by detection efficiency. Spin populations display relaxation dynamics consistent with simulations and theoretical predictions for $^{85}$Rb spin interactions, and contrary to the coherent spin waves witnessed in finite-temperature many-body experiments and zero-temperature two-body experiments. Our experimental approach offers a versatile platform for studying two-body quantum dynamics and may provide a route to thermally-robust entanglement generation.