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.


Demonstration of weighted graph optimization on a Rydberg atom array using local light-shifts
Neutral atom arrays have emerged as a versatile platform towards scalable quantum computation and optimisation. In this paper we present first demonstrations of weighted graph optimization on a Rydberg atom array using annealing with local light-shifts. We verify the ability to prepare weighted graphs in 1D and 2D arrays, including embedding a five vertex non-unit disk graph using nine physical qubits. We find common annealing ramps leading to preparation of the target ground state robustly over a substantial range of different graph weightings. This work provides a route to exploring large-scale optimisation of non-planar weighted graphs relevant for solving relevant real-world problems. For more details see arXiv:2404.02658.
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.



Paul Ireland

PhD student


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



We acknowledge funding from the following sources: