Scalable high-fidelity and near-deterministic preparation of large-photon-number states
Phys. Rev. A 114, 013721 – Published 24 July, 2026
DOI: https://doi.org/10.1103/f49z-hqgh
Abstract
The scalable preparation of large photon-number (Fock) states is a long-standing frontier in quantum science, with direct implications for quantum metrology and bosonic quantum information processing. Despite substantial progress at small photon numbers, extending state generation to large photon numbers while maintaining high fidelity and operating deterministically remains a significant challenge. Here, we demonstrate a scalable and experimentally accessible control protocol for generating large photon-number states using only native spin-oscillator operations. The protocol alternates Jaynes-Cummings interactions with phase-space displacements to imprint photon-number-dependent phases and convert them into selective interference in photon-number space. It already achieves high-preparation fidelity unconditionally, while an optional final qubit projection removes residual qubit-field correlations and further enhances the fidelity. Conditioned on this final projection, photon-number state preparation with fidelities exceeding 0.95 is achieved for photon numbers in the few-hundred regime, with a success probability exceeding 0.90, placing the protocol in a near-deterministic operating regime. The resulting control sequences remain shallow and are robust against detuning, control noise, and experimentally relevant dissipation. Our results establish a scalable and experimentally realistic paradigm for synthesizing large nonclassical bosonic resource states, with immediate implications for quantum metrology and bosonic quantum information processing.
