Objectivity in the Photonic Environment Through State Information Broadcasting

Abstract

Recently, the emergence of classical objectivity as a property of a quantum state has been explicitly derived for a small object embedded in a photonic environment in terms of a spectrum broadcast form---a specific classically correlated state, redundantly encoding information about the preferred states of the object in the environment. However, the environment was in a pure state and the fundamental problem was how generic and robust is the conclusion. Here we prove that despite of the initial environmental noise the emergence of the broadcast structure still holds, leading to the perceived objectivity of the state of the object. We also show how this leads to a quantum Darwinism-type condition, reflecting classicality of proliferated information in terms of a limit behavior of the mutual information. Quite surprisingly, we find ,,singular points'' of the decoherence, which can be used to faithfully broadcast a specific classical message through the noisy environment.