Photon counting statistics in the presence of spectral diffusion induced by nonequilibrium environmental fluctuations

Quantum Physics [Submitted on 15 Apr 2026] Photon counting statistics in the presence of spectral diffusion induced by nonequilibrium environmental fluctuations Xiangji Cai, Yonggang Peng, Yujun Zheng We theoretically investigate the statistical properties of photon emission of a driven two-level single-molecule system undergoing spectral diffusion induced by nonequilibrium environmental fluctuations. Within the framework of the generating function method and the stochastic Liouville equation, we analyze the influence of the nonequilibrium characteristics of environmental fluctuations respectively governed by nonstationary Ornstein-Uhlenbeck noise and random telegraph noise on the photon counting statistics of the driven single-molecule system. In the slow modulation limit of spectral diffusion, the intensity and statistical fluctuations of photon emission depend on the environmental nonequilibrium characteristics at short time scales, whereas they become independent of the nonequilibrium characteristics of environmental fluctuations in the steady state. In the fast modulation limit of spectral diffusion, neither the line shape nor the Mandel's parameter depends on the environmental nonequilibrium characteristics owing to the rapid relaxation of environmental fluctuations. These findings not only shed light on the role of nonequilibrium environmental fluctuations in shaping the photon emission properties of single-molecule systems but also provide a basis for distinguishing between equilibrium and nonequilibrium characteristics of environmental fluctuations in experimental measurements. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.13477 [quant-ph]   (or arXiv:2604.13477v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.13477 Focus to learn more Submission history From: Xiangji Cai [view email] [v1] Wed, 15 Apr 2026 04:58:31 UTC (531 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)