Condensed Matter Seminar: Logical qubit quantum computing with neutral atom arrays

Useful quantum computing will likely require large quantum computers with very low error rates, potentially achievable with quantum error correction (QEC). In QEC, errors are suppressed by nonlocally encoding information on logical qubits. I’ll review our recent report on a programmable logical-qubit quantum processor based on reconfigurable neutral atom arrays [1]. We realize up to 48 logical qubits and hundreds of entangling gates using up to 280 physical qubits, high gate fidelities [2], arbitrary connectivity, and parallel and arbitrary single-site control. We demonstrate fault-tolerant logical qubit preparation, a logical GHZ state preparation circuit and full state tomography, improvement of a two-qubit logic gate by scaling surface code distance (up to d=7), mid-circuit feed forward, and computationally complex circuits including many non-Clifford gates. We explore the latter via sampling and measurements of entanglement entropy. I’ll discuss our vision for large scale error-corrected quantum processors based on the key concepts of hardware-efficient transversal gates and a multi-zoned architecture, as well as the main challenges for further scaling. Time permitting, I’ll briefly touch on recent results in analog quantum simulation with atom arrays, including explorations of quantum coarsening and novel Hamiltonian engineering techniques. 

[1] Bluvstein et al. Nature (2023) 

[2] Evered et al. Nature (2023)