title: Quantum process nonclassicality.
abstract: We propose a definition of nonclassicality for a single-mode quantum-optical process based on its action on coherent states. If a quantum process transforms a coherent state to a nonclassical state, it is verified to be nonclassical. To identify nonclassical processes, we introduce a representation for quantum processes, called the process-nonclassicality quasiprobability distribution, whose negativities indicate nonclassicality of the process. Using this distribution, we derive a relation for predicting nonclassicality of the output states for a given input state. We experimentally demonstrate our method by considering the single-photon addition as a nonclassical process and predicting nonclassicality of the output state for an input thermal state.
authors.affiliation: Centre for Quantum Computation and Communication Technology, School of Mathematics and Physics, University of Queensland, Brisbane QLD 4072, Australia. s.rahimik@gmail.com
authors.forename: Saleh
authors.initials: S
authors.lastname: Rahimi-Keshari
authors.forename: Thomas
authors.initials: T
authors.lastname: Kiesel
authors.forename: Werner
authors.initials: W
authors.lastname: Vogel
authors.forename: Samuele
authors.initials: S
authors.lastname: Grandi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Zavatta
authors.forename: Marco
authors.initials: M
authors.lastname: Bellini