Neutral atom quantum processor with dynamically reconfigurable atoms
The neutral atom platform for quantum processing offers unique features, from scalable trapping of identical, high-coherence neutral-atom qubits to capabilities for parallel, high-fidelity gate operations. Our team at Harvard recently showed a new way to combine these features: by coherently moving atoms during a quantum circuit, we reconfigured the connectivity of the array to effectively enable arbitrary long-range gates. This coherent transport can be implemented in parallel on many atoms at once, which combines beautifully with the parallel implementation of two-qubit gates by illuminating the whole atom array with a Rydberg excitation laser: transport, entangle, transport, entangle, ... These features enable highly efficient implementation of many classes of quantum circuits, including those which are central building blocks for quantum error correction.
The two-qubit gate fidelities with neutral atoms are also steadily improving over time. Our team introduced a new gate protocol in 2019 (the "Pichler gate") that could be implemented by globally driving both atoms in the pair, enabling convenient parallel implementation across large systems. Our first gate fidelities were 97.4(3)%, and recent advances from the Harvard team including optimized variants of this gate and higher power lasers have now reached 99.5% fidelity.
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