Attosecond Access to the Quantum Noise of Light

Quantum Physics [Submitted on 15 Apr 2026] Attosecond Access to the Quantum Noise of Light En-Rui Zhou, Yi-Jia Mao, Pei-Lun He, Feng He Characterizing the quantum state of intense light fields on sub-cycle timescales remains beyond the reach of existing methods. Here, we show that attosecond streaking provides direct, phase-sensitive access to the quantum properties of the driving field through delay-resolved photoelectron spectra. Using a Feynman--Vernon treatment, we decompose the influence of the quantized driving field on the photoelectron into coherent and fluctuation contributions. This yields a simple, moment-based characterization of the light state: the first moment of the photoelectron momentum distribution reveals the coherent displacement, while the second central moment captures the fluctuation contribution and, for squeezed states, exhibits a clear modulation at twice the driving frequency, directly signaling phase-sensitive quantum noise. Time-dependent Schrödinger equation simulations confirm these relations and enable retrieval of the coherent phase, the squeezing phase, and the relative strengths of the coherent and fluctuation contributions from delay-resolved spectra. Taken together, these results establish attosecond streaking as a route to sub-cycle quantum-optical metrology in the strong-field regime. Comments: 6 pages, 2 figures Subjects: Quantum Physics (quant-ph); Atomic Physics (physics.atom-ph) Cite as: arXiv:2604.13485 [quant-ph]   (or arXiv:2604.13485v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.13485 Focus to learn more Submission history From: Pei-Lun He [view email] [v1] Wed, 15 Apr 2026 05:18:33 UTC (1,966 KB) Access Paper: view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 Change to browse by: physics physics.atom-ph 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?)