Two-detector reconstruction of multiphoton states in linear optical networks

Tudor-Alexandru Isdrailǎ

Jun-Yi Wu

Date of Publication

October 27, 2025

Centers

Quantum Computing Research Center

Topic

Quantum Computing

Table of Contents

We propose a method for partial state reconstruction of multiphoton states in multimode (𝑁-photon 𝑀-mode) linear optical networks (LONs) employing only two bucket photon-number-resolving detectors. The reconstructed Heisenberg-Weyl-reduced density matrix captures quantum coherence and symmetry with respect to Heisenberg-Weyl operators. Employing deterministic quantum computing with one qubit (DQC1) circuits, we reduce the detector requirement from 𝑀 to 2, while the requirement on measurement configurations is retained 2⁢𝑀3−2⁢𝑀. To ensure physicality, maximum likelihood estimation is incorporated into the DQC1 reconstruction process, with numerical simulations demonstrating the efficiency of our approach and its robustness against interferometer noises. This method offers a resource-efficient solution for state characterization in large-scale LONs to advance photonic quantum technologies.