Quantum cnot Gate with Actively Synchronized Photon Pairs
Phys. Rev. Lett. 135, 260806 – Published 26 December, 2025
DOI: https://doi.org/10.1103/c318-t2vn
Abstract
Controlling the synchronization of photons from probabilistic quantum sources plays a pivotal role in advancing efficient quantum information processing. We report the realization of a probabilistic entangling gate operating on actively synchronized photon pairs, using a quantum memory based on warm atomic vapor. We achieve a truth-table fidelity exceeding 85% and demonstrate Bell-inequality violation for all four Bell states. The reduction in visibility of the Hong-Ou-Mandel interference introduced by the storage process is identified as a primary factor limiting the gate fidelity. We derive an exact quantitative relation between Hong-Ou-Mandel visibility and gate fidelity for pure single photons, which applies to all photonic gates relying on interference, regardless of the physical platform.
Physics Subject Headings (PhySH)
Corrections
8 April, 2026
Correction: The omission of a support statement in the Acknowledgments has been fixed.
