Quantum-to-classical transition via fuzzy measurements on high-gain spontaneous parametric down-conversion
Authors: Vitelli C., Spagnolo N., Toffoli L., Sciarrino F., De Martini F.
Autors Affiliation: Dipartimento di Fisica, “Sapienza” Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy; Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Piazzale Aldo Moro 5, I-00185 Roma, Italy; Istituto Nazionale di Ottica Applicata, Largo Fermi 6, I-50125 Firenze, Italy; Accademia Nazionale dei Lincei, via della Lungara 10, I-00165 Roma, Italy
Abstract: We consider the high-gain spontaneous parametric down-conversion in a noncollinear geometry as a paradigmatic scenario to investigate the quantum-to-classical transition by increasing the pump power, that is, the average number of generated photons. The possibility of observing quantum correlations in such a macroscopic quantum system through dichotomic measurement will be analyzed by addressing two different measurement schemes, based on different dichotomization processes. More specifically, we will investigate the persistence of nonlocality in an increasing size n/2-spin singlet state by studying the change in the correlations form as n increases, both in the ideal case and in presence of losses. We observe a fast decrease in the amount of Bell\’s inequality violation for increasing system size. This theoretical analysis is supported by the experimental observation of macro-macro correlations with an average number of photons of about 10(3). Our results shed light on the practical extreme difficulty of observing nonlocality by performing such a dichotomic fuzzy measurement.
Journal/Review: PHYSICAL REVIEW A
Volume: 81 (3) Pages from: 032123 to: 032123
KeyWords: quantum mechanics; measurement theory; optical tests of quantum theoryDOI: 10.1103/PhysRevA.81.032123Citations: 26data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-02-23References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here