High-fidelity entangling gates and nonlocal circuits with neutral atoms

TL;DR

This paper demonstrates high-fidelity entangling gates with neutral atoms, achieving state-of-the-art fidelities and applying them to complex quantum circuits, advancing fault-tolerant quantum computing.

Contribution

It introduces a neutral-atom quantum processor with high-fidelity CZ gates and applies these gates to create and analyze nonlocal entangled states and scrambling circuits.

Findings

Achieved 99.854% fidelity for entangling CZ gates.

Fidelities improve to 99.941% with loss postselection.

Successfully implemented complex quantum circuits with stable performance.

Abstract

Creation and manipulation of entanglement with low error is essential in quantum information systems. In practice, two-qubit entangling gates constitute a dominant error source, limiting circuit depths and performance in fault-tolerant architectures. Using a neutral-atom quantum processor, we realize entangling CZ gates with a high Rabi frequency smooth-amplitude pulse, employing state-selective readout and qubit reuse for fast calibration, and achieve state-of-the-art fidelities of 99.854(4)% which improve to 99.941(3)% upon loss postselection, with stable performance for 10 hours. We then use these low-error gates in quantum circuits with coherent atom rearrangement. We first benchmark performance by creating and disentangling cluster states, and subsequently implement scrambling circuits featuring longer-range connectivity to study non-locally entangled states generated through chaotic dynamics. These results pave the way towards deep-circuit, efficient fault-tolerant quantum computation.