Engineering Non-Gaussian Bosonic Gates through Quantum Signal Processing

Abstract:Non-Gaussian operations are essential for most bosonic quantum technologies. Yet, realizable non-Gaussian gates are rather limited in type and generally suffer from accuracy-duration trade-offs. In this work, we propose to use quantum signal processing (QSP) techniques to engineer non-Gaussian gates on hybrid qumode-qubit systems. For systems with dispersive coupling, our scheme can generate a new non-Gaussian gate that produces a phase shift depending on the modulus of the boson number. This gate reproduces the selective number-dependent arbitrary phase (SNAP) gates under certain parameter choices, but with higher accuracy within a short, fixed and excitation-independent interaction time. The gate unlocks new applications, for example, in entangling logical qudits and deterministically generating multi-component cat states. Additionally, our versatile QSP formalism can be extended to systems with other interactions, and also engineer non-unitary operations, such as noiseless linear amplification and generalized-parity measurement.

arXiv:2508.20261 [quant-ph]

(or arXiv:2508.20261v3 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2508.20261 Focus to learn more arXiv-issued DOI via DataCite

Phys. Rev. A 114, 032608 (2026)

https://doi.org/10.1103/gdbf-cjz4 Focus to learn more DOI(s) linking to related resources

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