Universal Fidelity Law for Linear-Optical Entangling Gates

Abstract:Imperfect photon sources degrade the performance of interference-based linear-optical entangling gates. We derive a universal fidelity law for these gates in terms of two standard source metrics: Hong-Ou-Mandel visibility and second-order coherence. We model the multiphoton component as an arbitrary overlap between noise and signal photons. While different values of the signal-noise overlap produce different error structures, associated with different physical platforms, all result in the same fidelity law. We test the model on our actively synchronized CNOT-gate experiment and against published results across different platforms, with no free parameters. This framework turns source characterization into a unified benchmark for photonic quantum computing.

Quantum Physics (quant-ph); Atomic Physics (physics.atom-ph); Optics (physics.optics)

arXiv:2609.25861 [quant-ph]

(or arXiv:2609.25861v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.25861 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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