title: Qubit-Programmable Operations on Quantum Light Fields.
abstract: Engineering quantum operations is a crucial capability needed for developing quantum technologies and designing new fundamental physics tests. Here we propose a scheme for realising a controlled operation acting on a travelling continuous-variable quantum field, whose functioning is determined by a discrete input qubit. This opens a new avenue for exploiting advantages of both information encoding approaches. Furthermore, this approach allows for the program itself to be in a superposition of operations, and as a result it can be used within a quantum processor, where coherences must be maintained. Our study can find interest not only in general quantum state engineering and information protocols, but also details an interface between different physical platforms. Potential applications can be found in linking optical qubits to optical systems for which coupling is best described in terms of their continuous variables, such as optomechanical devices.
authors.affiliation: Dipartimento di Scienze, Università degli Studi Roma Tre, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Barbieri
authors.affiliation: Dipartimento di Fisica, Sapienza Università di Roma, Rome, Italy.
authors.forename: Nicolò
authors.initials: N
authors.lastname: Spagnolo
authors.affiliation: Laboratoire Photonique, Numérique et Nanostructures, Institut d'Optique, CNRS and Université de Bordeaux, Talence, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Ferreyrol
authors.affiliation: Centre for Quantum Computation and Communication Technology, School of Mathematics and Physics, University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Rémi
authors.initials: R
authors.lastname: Blandino
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, United Kingdom.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Smith
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique, CNRS and Université Paris-Sud, Palaiseau, France and Institut Universitaire de France, Paris, France.
authors.forename: Rosa
authors.initials: R
authors.lastname: Tualle-Brouri