Quantum-walk measurements with sequential imaging of the same atomic sample

Abstract

We demonstrate sequential single-atom-resolved imaging of the same ultracold atomic sample and apply this technique to quantum-walk measurements in an optical lattice. In quantum gas microscope experiments, fluorescence imaging provides microscopic information on atomic distributions but induces motional heating through photon scattering, making it difficult to reuse the same sample for subsequent quantum dynamics. To overcome this limitation, we apply Raman sideband cooling with parameters optimized for post-imaging cooling, enabling sequential single-atom-resolved measurements of the same sample. By optimizing the cooling parameters with machine learning, we achieve high fidelity over multiple imaging cycles. To demonstrate the capability of this technique, we measure one-dimensional quantum walks of single atoms in an optical lattice. By determining the initial atomic positions from fluorescence images, we extract quantum-walk transition probabilities without requiring deterministic preparation of the initial atomic positions. The observed dynamics agree with numerical simulations of quantum walks of single atoms. Our method provides a route toward reducing experimental overhead in quantum gas microscope studies requiring repeated acquisition of spatially resolved correlation data.