Quantum many-body physics with single atoms in optical tweezers

Philippe Grangier

Matthew A. Norcia, Aaron W. Young, Adam M. Kaufman

Optical tweezers provide a versatile platform for the manipulation and detection of single atoms.Here, we use optical tweezers to demonstrate a set of tools for the microscopic control of atomic strontium, which has two valence electrons.Compared to the single-valence-electron atoms typically used with tweezers, strontium has a more complex internal state structure with a variety of transition wavelengths and linewidths.We report single-atom loading into an array of subwavelength scale optical tweezers and lightshift-free control of a narrow-linewidth optical transition.We use this transition to perform threedimensional ground-state cooling and to enable high-fidelity nondestructive imaging of single atoms on subwavelength spatial scales.These capabilities, combined with the rich internal structure of strontium, open new possibilities including tweezer-based metrology, new quantum computing architectures, and new paths to low-entropy many-body physics.

Yichao Yu, Lee R. Liu, Kenneth Wang +4 more

Mikkel F. Andersen, Pimonpan Sompet, Eyal Schwartz +1 more

Summary form only given. Complete control of individual atoms trapped in far-off resonance optical tweezers is vital for gaining a better understanding of the microscopic world. It will provide a platform with unprecedented flexibility for studying few-body physics, and might lead to new quantum technologies. By combining near-deterministic preparation of single atoms [1-3] with Zeeman-insensitive Raman sideband cooling [4], we present a push button method to prepare a single 85Rb atom in its centre of mass ground state with high fidelity. Our Raman sideband cooling scheme works efficiently in an environment with magnetic field fluctuations that were too large for other Raman sideband cooling variations [5,6]. In 2D, we achieve a fidelity for the entire loading procedure of ~0.7 for a single atom in the ground state of the optical tweezers. In 3D, the fidelity drops to 0.1 since the cooling is less efficient for the weakly confined tweezer axis.

Philippe Grangier

May E. Kim, Tzu-Han Chang, Brian M. Fields +2 more

Trapped atoms near nanophotonics form an exciting platform for bottom-up synthesis of strongly interacting quantum matter. The ability to induce tunable long-range atom-atom interactions with photons presents an opportunity to explore many-body physics and quantum optics. Here we implement a configurable optical tweezer array over a planar photonic circuit tailored for cold atom integration and control for trapping and high-fidelity imaging of one or more atoms in an array directly on a photonic structure. Using an optical conveyor belt formed by a moving optical lattice within a tweezer potential, we show that single atoms can be transported from a reservoir into close proximity of a photonic interface, potentially allowing for the synthesis of a defect-free atom-nanophotonic hybrid lattice. Our experimental platform can be integrated with generic planar photonic waveguides and resonators, promising a pathway towards on-chip many-body quantum optics and applications in quantum technology.