title: Physical realization of the Glauber quantum oscillator.
abstract: More than thirty years ago Glauber suggested that the link between the reversible microscopic and the irreversible macroscopic world can be formulated in physical terms through an inverted harmonic oscillator describing quantum amplifiers. Further theoretical studies have shown that the paradigm for irreversibility is indeed the reversed harmonic oscillator. As outlined by Glauber, providing experimental evidence of these idealized physical systems could open the way to a variety of fundamental studies, for example to simulate irreversible quantum dynamics and explain the arrow of time. However, supporting experimental evidence of reversed quantized oscillators is lacking. We report the direct observation of exploding n = 0 and n = 2 discrete states and Γ0 and Γ2 quantized decay rates of a reversed harmonic oscillator generated by an optical photothermal nonlinearity. Our results give experimental validation to the main prediction of irreversible quantum mechanics, that is, the existence of states with quantized decay rates. Our results also provide a novel perspective to optical shock-waves, potentially useful for applications as lasers, optical amplifiers, white-light and X-ray generation.
authors.affiliation: Institute for Complex Systems, National Research Council, Via dei Taurini 19, 00185 Rome (IT).|Department of Physics, University Sapienza, Piazzale Aldo Moro 5, 00185 Rome (IT).
authors.forename: Silvia
authors.initials: S
authors.lastname: Gentilini
authors.affiliation: Institute for Complex Systems, National Research Council, Via dei Taurini 19, 00185 Rome (IT).|Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio 10, I-67010 L'Aquila (IT).
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Braidotti
authors.affiliation: Department of Physics, University Sapienza, Piazzale Aldo Moro 5, 00185 Rome (IT).
authors.forename: Giulia
authors.initials: G
authors.lastname: Marcucci
authors.affiliation: Institute for Complex Systems, National Research Council, Via dei Taurini 19, 00185 Rome (IT).|Department of Physics, University Sapienza, Piazzale Aldo Moro 5, 00185 Rome (IT).
authors.forename: Eugenio
authors.initials: E
authors.lastname: DelRe
authors.affiliation: Institute for Complex Systems, National Research Council, Via dei Taurini 19, 00185 Rome (IT).|Department of Physics, University Sapienza, Piazzale Aldo Moro 5, 00185 Rome (IT).
authors.forename: Claudio
authors.initials: C
authors.lastname: Conti