Holevo bound and objectivity in the boson-spin model

TL;DR

This paper analyzes how classical information emerges from quantum systems by calculating the Holevo bound in a boson-spin model, revealing how information capacity depends on various physical parameters.

Contribution

It applies quantum channel theory to a boson-spin model, providing new insights into information broadcasting and the emergence of objectivity in quantum systems.

Findings

Initial capacity grows quadratically with time

Maximum Holevo bound depends on temperature and tunneling energy

Identifies regimes with optimal information broadcasting

Abstract

Emergence of objective, classical properties in quantum systems can be described in the modern language of quantum information theory. In this work, we present an example of such an analysis. We apply the quantum channel theory to a boson-spin model of open quantum systems and calculate, using recoilless approximation and the Floquet theory, the Holevo quantity, which bounds the capacity of the channel, broadcasting information about the central system into its environment. We analyze both the short-time regime, showing quadratic in time initial growth of the capacity, and the asymptotic regime. Complicated dependence on the model parameters, such as temperature, tunneling energy for the environment, etc., is also analyzed, showing, e.g., regimes where the Holevo bound reaches its maximum.