Redundant Information from Thermal Illumination: Quantum Darwinism in Scattered Photons

TL;DR

This paper investigates how the size and initial state of a blackbody illumination source affect the quantum Darwinism process, revealing that larger sources produce less redundant information about a system.

Contribution

It provides a detailed calculation of quantum mutual information for arbitrary sky sections, demonstrating the impact of source size and initial state on information redundancy.

Findings

Extended sources reduce the creation of redundant information.

Initial mixedness of the environment slows information recording.

Results are robust for various initial system states.

Abstract

We study quantum Darwinism, the redundant recording of information about the preferred states of a decohering system by its environment, for an object illuminated by a blackbody. We calculate the quantum mutual information between the object and its photon environment for blackbodies that cover an arbitrary section of the sky. In particular, we demonstrate that more extended sources have a reduced ability to create redundant information about the system, in agreement with previous evidence that initial mixedness of an environment slows---but does not stop---the production of records. We also show that the qualitative results are robust for more general initial states of the system.