Quantum error correction is crucial for scalable quantum information processing applications. Traditional discrete-variable quantum codes that use multiple two-level systems to encode logical information can be hardware-intensive. An alternative approach is provided by bosonic codes, which use the infinite-dimensional Hilbert space of harmonic oscillators to encode quantum information. In this project, my co-authors and I investigate the performance of bosonic quantum error correction protocols. We focus on the performance of bosonic codes in the presence of realistic noise models, and on the development of new error correction protocols and decoders with a focus on the utilization of analog information.
References
2025
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Linear-Optical Quantum Computation with Arbitrary Error-Correcting Codes
Blayney W. Walshe, Ben Q. Baragiola, Hugo Ferretti, José Gefaell, Michael Vasmer, Ryohei Weil, and 8 more authors
Phys. Rev. Lett., Mar 2025
High-rate quantum error-correcting codes mitigate the imposing scale of fault-tolerant quantum computers but require efficient generation of nonlocal, many-body entanglement. We provide a linear-optical architecture with these properties, compatible with arbitrary codes and Gottesman-Kitaev-Preskill qubits on generic lattices, and featuring a natural way to leverage physical noise bias. Simulations of hyperbolic surface codes and bivariate bicycle codes, promising families of quantum low-density parity-check codes, reveal a threshold comparable to the 2D surface code with substantially better encoding rates.
2023
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Quantum error correction with dissipatively stabilized squeezed-cat qubits
Timo Hillmann, and Fernando Quijandría
Phys. Rev. A, Mar 2023
Noise-biased qubits are a promising route toward significantly reducing the hardware overhead associated with quantum error correction. The squeezed-cat code, a nonlocal encoding in phase space based on squeezed coherent states, is an example of a noise-biased (bosonic) qubit with exponential error bias. Here we propose and analyze the error correction performance of a dissipatively stabilized squeezed-cat qubit. We find that for moderate squeezing the bit-flip error rate gets significantly reduced in comparison with the ordinary cat qubit while leaving the phase-flip rate unchanged. Additionally, we find that the squeezing enables faster and higher-fidelity gates.
2022
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