2020/05/31 by Jiyong Park, Jaehak Lee, Hyunchul Nha
Computer Science · Mathematics · Physics and Astronomy · #Computer science #Dimension (graph theory) #Gaussian #Mathematics #Negativity effect #Phase space #Physics #Pure mathematics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum mechanics #Quantum state #Spectroscopy and Quantum Chemical Studies #Statistical physics #quant-ph
paper · pdf · doi:10.1103/physrevresearch.3.043116
published as Phys. Rev. Research 3, 043116 (2021) · 7+10 pages, 3+11 figures, close to published version
openalex publication_date 2021/11/15 · arxiv created 2021/12/29 · arxiv updated 2021/12/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
While negativity in phase space is a well-known signature of nonclassicality, a wide variety of nonclassical states require their characterization beyond negativity. We establish a framework of nonclassicality in phase space that addresses nonclassical states comprehensively with a direct experimental evidence. This includes the negativity of phase-space distribution as a special case and further analyzes quantum states with positive distributions effectively. We prove that it detects all nonclassical Gaussian states and all non-Gaussian states of arbitrary dimension remarkably by examining three phase-space points only. Our formalism also provides an experimentally accessible lower bound for a nonclassicality measure based on trace distance. Importantly, this foundational approach can be further adapted to constitute practical tests in two directions looking into particle and wave nature of bosonic systems, via an array of nonideal on-off detectors and coarse-grained homodyne measurement, respectively. All these tests are practically powerful in characterizing nonclasssical states reliably against noise, making a versatile tool for a broad range of quantum systems in quantum technologies.