Neutral atom arrays have emerged as a powerful platform for quantum computation, simulation, and metrology.Among them, alkaline-earth-like atoms exhibit distinct advantages, including long coherence time, high-fidelity Rydberg gates, and erasure correction for efficient quantum error correction. However, their scalability has lagged behind that of the alkali atoms. Here, we report 2400 ytterbium-174 atoms trapped in an optical tweezer array with enhanced loading efficiency of 83.5(1)\% via blue-detuned light-assisted collisions. We develop a quantitative model of the collision dynamics and find good agreement between the calculated inelastic collision rates and the experimentally measured loading efficiencies.Notably, the loading efficiency is largely maintained for array sizes ranging from dozens to thousands, exhibiting excellent scalability. We further demonstrate that the enhancement exists robustly across a range of interatomic potentials, suggesting its utility for other atomic species. To establish the capability of the
174Yb arrays toward universal quantum computation, we propose to encode the qubit in the ground-clock state manifold and estimate a 99.9\% two-qubit gate fidelity with experimentally feasible parameters. Our work advances the prospects for realizing large-scale quantum computers using alkaline-earth-like atoms.
Robust cooling and nondestructive imaging are prerequisites for many emerging applications of neutral atoms trapped in optical tweezers, such as their use in quantum information science and analog quantum simulation. The tasks of cooling and imaging can be challenged, however, by the presence of large trap-induced shifts of their respective optical transitions. Here, we explore a system of
39K atoms trapped in a near-detuned (
780 nm) optical tweezer, which leads to relatively minor differential (ground vs. excited state) Stark shifts. We demonstrate that simple and robust loading, cooling, and imaging can be achieved through a combined addressing of the D
1 and D
2 transitions. While imaging on the D
2 transition, we can simultaneously apply
Λ-enhanced gray molasses (GM) on the D
1 transition, preserving low backgrounds for single-atom imaging through spectral filtering. Using D
1 cooling during and after trap loading, we demonstrate enhanced loading efficiencies as well as cooling to low temperatures. These results suggest a simple and robust path for loading and cooling large arrays of potassium atoms in optical tweezers through the use of resource-efficient near-detuned optical tweezers and GM cooling.
In this talk, I will discuss our pathway toward quantum simulations and computation with neutral atoms in arrays of optical tweezers cooled to their motional ground state. Initially, I will talk about two-atom interference experiments, e.g. the atomic analog to the Hong-Ou-Mandel effect, and how we create spin entangled states. I will then talk about how we scale our system to accommodate 80 single atoms, loaded into 100 traps while maintaining full single-atom control. For this efficient loading process, we control atomic collisions in the tweezers using grey molasses. When combined with ground-state cooling and atom-rearranging, this should allow us to form a micro-BEC with controlled atom number and entropy.
Scaling the size of assembled neutral-atom arrays trapped in optical lattices or optical tweezers is an enabling step for a number of applications ranging from quantum simulations to quantum metrology. However, preparation times increase with system size and constitute a severe bottleneck in the bottom-up assembly of large ordered arrays from stochastically loaded optical traps. Here we demonstrate a method to circumvent this bottleneck by recycling atoms from one experimental run to the next, while continuously reloading and adding atoms to the array. Using this approach, we achieve densely packed arrays with more than 1000 atoms stored in an optical lattice, continuously refilled with a 3.5 s cycle time and about 130 atoms reloaded during each cycle. Furthermore, we show that we can continuously maintain such large arrays by simply reloading atoms that are lost from one cycle to the next. Our approach paves the way towards quantum science with large ordered atomic arrays containing thousands of atoms in continuous operation. Published by the American Physical Society 2024
Robust cooling and nondestructive imaging are prerequisites for many emerging applications of neutral atoms trapped in optical tweezers, such as their use in quantum information science and analog quantum simulation.The tasks of cooling and imaging can be challenged, however, by the presence of large trap-induced shifts of their respective optical transitions.Here, we explore a system of 39 K atoms trapped in a near-detuned (780 nm) optical tweezer, which leads to relatively minor differential (ground versus excited state) Stark shifts.We demonstrate that simple and robust loading, cooling, and imaging can be achieved through combined addressing of the D 1 and D 2 transitions.While imaging on the D 2 transition, we can simultaneously apply -enhanced gray molasses (GM) on the D 1 transition, preserving low backgrounds for single-atom imaging through spectral filtering.Using D 1 cooling during and after trap loading, we demonstrate enhanced loading efficiencies as well as cooling to low temperatures.These results suggest a simple and robust path for loading and cooling large arrays of potassium atoms in optical tweezers through the use of resource-efficient near-detuned optical tweezers and GM cooling.