We introduce a measure to quantify the non-Gaussian character of a quantum state: the quantum relative entropy between the state under examination and a reference Gaussian state. We analyze in detail the properties of our measure and illustrate its relationships with relevant quantities in quantum information such as the Holevo bound and the conditional entropy; in particular, a necessary condition for the Gaussian character of a quantum channel is also derived. The evolution of non-Gaussianity is analyzed for quantum states undergoing conditional Gaussification toward twin beams and de-Gaussification driven by Kerr interaction. Our analysis allows us to assess non-Gaussianity as a resource for quantum information and, in turn, to evaluate the performance of Gaussification and de-Gaussification protocols.
|Titolo:||Quantifying the non Gaussian character of a quantum state by quantum relative entropy|
PARIS, MATTEO (Secondo)
|Parole Chiave:||entropy ; optical Kerr effect ; protocols ; quantum entanglement ; quantum optics ; teleportation|
|Settore Scientifico Disciplinare:||Settore FIS/03 - Fisica della Materia|
|Data di pubblicazione:||2008|
|Digital Object Identifier (DOI):||10.1103/PhysRevA.78.060303|
|Appare nelle tipologie:||01 - Articolo su periodico|