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arXiv:2404.11193 · Machine Learning Science and Technology

Photonic indistinguishability characterization and optimization for cavity-based single-photon source

Miao Cai, Mingyuan Chen, Jiang-Shan Tang, Keyu Xia

Published Jul 28, 2025• 0 citations
arXivHTMLPDF

Abstract

Abstract Indistinguishability of single photons from independent sources is critically important for scalable quantum technologies. We provide a comprehensive comparison of single-photon indistinguishability of different kinds of cavity quantum electrodynamics (CQEDs) systems by numerically simulating Hong–Ou–Mandel two-photon interference. We find that the CQED system using natural atoms exhibits superiority in indistinguishability, benefiting from the inherently identical features. Moreover, a Λ − type three-level atom shows essential robustness against variation of various system parameters because it exploits the two ground states with considerably smaller decay rates for single-photon generation. Furthermore, a machine learning-based framework is proposed to significantly and robustly improve single-photon indistinguishability for two non-identical CQED systems. This work may pave the way for designing and engineering reliable and scalable photon-based quantum technologies.

DOI
10.1088/2632-2153/adf53c

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Abstract Indistinguishability of single photons from independent sources is critically important for scalable quantum technologies. We provide a comprehensive comparison of single-photon indistinguishability of different kinds of cavity quantum electrodynamics (CQEDs) systems by numerically simulating Hong–Ou–Mandel two-photon interference. We find that the CQED system using natural atoms exhibits superiority in indistinguishability, benefiting from the inherently identical features. Moreover, a Λ − type three-level atom shows essential robustness against variation of various system parameters because it exploits the two ground states with considerably smaller decay rates for single-photon generation. Furthermore, a machine learning-based framework is proposed to significantly and robustly improve single-photon indistinguishability for two non-identical CQED systems. This work may pave the way for designing and engineering reliable and scalable photon-based quantum technologies.
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We investigate two schemes for generating indistinguishable single photons, a key feature of quantum networks, from a trapped ion coupled to an optical cavity. Through selection of the initial state in a cavity-assisted Raman transition, we suppress the detrimental effects of spontaneous emission on the photon's coherence length, measuring a visibility of 81(2)81(2)%81(2) without subtraction of background counts in a Hong-Ou-Mandel interference measurement, the highest reported for an ion-cavity system. In comparison, a visibility of 50(2)% was measured using a more conventional single-photon scheme. We demonstrate through numerical analysis of the single-photon generation process that our scheme produces photons of a given indistinguishability with a greater efficiency than the conventional one. Single-photon schemes such as the one demonstrated here have applications in distributed quantum computing and communications, which rely on high-fidelity entanglement swapping and state transfer through indistinguishable single photons.
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We present a quantum jump/trajectory analysis of the two-photon interference phenomenon in the context of the Hong–Ou–Mandel (HOM) effect. In particular, we consider the standard setup of the HOM effect, which consists of two-photon sources firing single photons from opposite sides of a 50/50 beam splitter and two perfect detectors placed at the output ports to record photodetection events. For single-photon sources, we consider two special cases: (1) two excited two-level atoms and (2) two atom–cavity setups with initially present single photons in both cavities. For both cases, we report analytic results as well as quantum jump-based Monte Carlo simulations to demonstrate the signatures of these single-photon sources on the HOM effect under different working conditions (e.g., strong- and weak-coupling regimes of cavity quantum electrodynamics). The HOM effect offers applications in the areas of linear optics quantum computing, as well as in protocols that test the indistinguishability of single-photon sources.