Quantum Error Correction in dual-species Rydberg arrays

This project, supported by a Royal Academy of Engineering Senior Research Fellowship, M Squared Lasers and EPSRC, seeks to develop a new experiment focused on creating dual-species arrays of Cs and Rb for quantum error correction. This is integrated within a 4K closed-cycle cryostat to obtain extended trap lifetime for scaling to large numbers of qubits, and will focus on exploiting long-range dipole interactions between Rydberg states of each species to enable mid-circuit, non-destructive readout and generation of topologically protected logical qubits as a route towards fault tolerant digital quantum computing.

Early objectives for the project are to precisely measure and characterise Cs and Rb interaction strengths, and exploit the a novel gate protocol based on electromagnetically induced transparency previously demonstrated by our team for a pair of atoms (Phys. Rev. Lett. 129, 200501 (2022)) to perform stabiliser operations as a precursor to implementing quantum error correction codes.

Highlights

First 4K Cs MOT!
We have trapped our first cold Cs MOT inside the 4K region of the cryostat, running the MOT with superconducting coils. This is the first step towards generating large, reconfigurable arrays of individually trapped atoms, and will soon be followed by the first cold Rb atoms as the new cooling laser system is assembled.
Interspecies Förster resonances of Rb-Cs Rydberg d-states for enhanced multi-qubit gate fidelities
We present an analysis of interspecies interactions between Rydberg d-states of rubidium and cesium. We identify the Förster resonance channels offering the strongest interspecies couplings, demonstrating the viability for performing high-fidelity two- and multi-qubit CkZ gates up to k=4, including accounting for blockade errors evaluated via numerical diagonalization of the pair-potentials. Our results show d-state orbitals offer enhanced suppression of intraspecies couplings compared to s-states, making them well suited for use in large-scale neutral atom quantum processors. For more details see arXiv:2401.02308.

Team

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Dr Kieran Craig

Postdoc

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Ian Moodie

PhD student

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Paul Ireland

PhD student

Publications

Interspecies Förster resonances for Rb-Cs Rydberg d-states for enhanced multi-qubit gate fidelities. Physical Review Research 6, 013293 (2024).

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Funding

We acknowledge funding from the following sources: