Quantum Advantage for Single-Photon State Characterization
Phys. Rev. Lett. 137, 073604 – Published 12 August, 2026
DOI: https://doi.org/10.1103/g28d-jzgj
Abstract
We propose a multiphoton interference protocol that characterizes the pairwise overlaps of the internal modes of single photons more efficiently than pairwise Hong-Ou-Mandel characterization experiments. We experimentally implement this protocol to characterize three photons. We show that our implementation of the characterization protocol outperforms the pairwise Hong-Ou-Mandel characterization, even if the Hong-Ou-Mandel characterization would have been performed in a noiseless, perfect experiment. We demonstrate this via the Fisher information matrix. Surprisingly, this advantage persists at arbitrary nonzero transmission, demonstrating the viability of this protocol for real-world characterization of single photons.
