Achieving High Filling of an Optical Lattice by Light-Assisted Redistribution of Atoms

TL;DR

This paper demonstrates a light-assisted redistribution method in optical lattices that significantly increases atom filling fractions, surpassing previous limits imposed by light-assisted collisions.

Contribution

The authors introduce a stochastic redistribution process during cooling that achieves 70-80% atom filling, improving scalability for quantum applications.

Findings

Achieved 70-80% single-atom filling fractions in optical lattices.

Retained over 50% of atoms involved in radiative collisions.

Demonstrated a scalable method to reach near-unity atom filling without complex rearrangements.

Abstract

Scalable arrays of individual atoms provide an ideal starting point for quantum information and simulation experiments. However, their preparation is often limited by light-assisted collisions (LACs), which typically result in parity-projected filling fractions of $f \approx 0.5$. In this work we demonstrate a light-assisted redistribution process in the Quantum Matter Synthesizer that overcomes this constraint by stochastically moving atoms from multiply occupied lattice sites to neighboring vacant sites. Using a blue-detuned optical pumping beam during degenerate Raman sideband cooling, we achieve single-atom filling fractions of $70-80\%$. We find that over 50$\%$ of the atoms involved in radiative collisions are retained in the lattice. The redistribution process involves many LACs over an extended time as atoms diffuse to empty sites. Our demonstration offers a scalable and efficient pathway toward unity-filled atom arrays without the need for complex rearrangement protocols, with broad applicability to quantum simulation, precision measurements, and quantum information control.