title: Temporal Quantum Correlations in Inelastic Light Scattering from Water.
abstract: Water is one of the most prevalent chemicals on our planet, an integral part of both our environment and our existence as a species. Yet it is also rich in anomalous behaviors. Here we reveal that water is a novel-yet ubiquitous-source for quantum correlated photon pairs at ambient conditions. The photon pairs are produced through Raman scattering, and the correlations arise from the shared quantum of a vibrational mode between the Stokes and anti-Stokes scattering events. We confirm the nonclassical nature of the produced photon pairs by showing that the cross-correlation and autocorrelations of the signals violate a Cauchy-Schwarz inequality by over 5 orders of magnitude. The unprecedented degree of violating the inequality in pure water, as well as the well-defined polarization properties of the photon pairs, points to its usefulness in quantum information.
authors.affiliation: Photonics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Mark
authors.initials: M
authors.lastname: Kasperczyk
authors.affiliation: Departamento de Física, Universidade Federal de Minas Gerais, Belo Horiztone, Minas Gerais 31270-901, Brazil.
authors.forename: Filomeno S
authors.initials: FS
authors.lastname: de Aguiar Júnior
authors.affiliation: Programa de Pós-Graduação em Engenharia Elétrica, Universidade Federal de Minas Gerais, Belo Horiztone, Minas Gerais 31270-901, Brazil.
authors.forename: Cassiano
authors.initials: C
authors.lastname: Rabelo
authors.affiliation: Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-972, Brazil.
authors.forename: Andre
authors.initials: A
authors.lastname: Saraiva
authors.affiliation: Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-972, Brazil.
authors.forename: Marcelo F
authors.initials: MF
authors.lastname: Santos
authors.affiliation: Photonics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Novotny
authors.affiliation: Departamento de Física, Universidade Federal de Minas Gerais, Belo Horiztone, Minas Gerais 31270-901, Brazil.
authors.forename: Ado
authors.initials: A
authors.lastname: Jorio