Investigation on the quantum-to-classical transition by optical parametric amplification: Generation and detection of multiphoton quantum superposition

摘要

We review an extended research carried out on the theoretical and experimental realization of a macroscopic quantum superposition (MQS) made up with photons. The described scheme is based on a nonlinear process, the quantum injected optical parametric amplification, that transforms the quantum coherence or a single particle state, i.e. a Micro-qubit, into a Macro-qubit, consisting in a large number M of photons in quantum superposition. Since the adopted scheme was Found resilient to decoherence, the MQS demonstration was carried out experimentally at room temperature with M >= 10(4) This result elicited an extended study on quantum cloning, quantum amplification and quantum decoherence. The MQS interference patterns for large M were revealed in the experiment and the bipartite Micro-Macro entanglement was also demonstrated for a limited number of generated particles. At last, the perspectives opened by this new method are considered in the view of further studies on quantum foundations and quantum measurement. (C) 2014 Published by Elsevier B.V.