Wigner-function theory and decoherence of the quantum-injected optical parametric amplifier

TL;DR

This paper analyzes how quantum superposition states generated by a Quantum Injected Optical Parametric Amplifier (QIOPA) evolve under loss, using Wigner functions to assess their non-classicality and resilience to decoherence.

Contribution

It provides a theoretical investigation of the decoherence effects on multiphoton quantum states via Wigner function evolution, highlighting differences with coherent state superpositions.

Findings

Negative regions in Wigner functions indicate non-classicality.

QIOPA-generated states show high resilience to losses.

Comparison reveals both differences and similarities with coherent state superpositions.

Abstract

Recent experimental results demonstrated the generation of a quantum superpositon (MQS), involving a number of photons in excess of 5x10^4, which showed a high resilience to losses. In order to perform a complete analysis on the effects of de-coherence on this multiphoton fields, obtained through the Quantum Injected Optical Parametric Amplifier (QIOPA), we invesigate theoretically the evolution of the Wigner functions associated to these states in lossy conditions. Recognizing the presence of negative regions in the W-representation as an evidence of non-classicality, we focus our analysis on this feature. A close comparison with the MQS based on coherent states allows to identify differences and analogies.