Decoherence and objectivity in higher spin environments

TL;DR

This paper provides a comprehensive analysis of decoherence and objectivization in higher spin environments, deriving exact formulas and exploring how increased spin enhances these quantum processes, extending previous spin-1/2 studies.

Contribution

It generalizes previous spin-1/2 models to arbitrary spins, offering analytic formulas for decoherence and objectivization, and investigates the influence of higher spins on these processes.

Findings

Higher spins lead to more efficient decoherence.

Objectivization improves with increasing spin.

Analytic formulas for decoherence and fidelity are derived.

Abstract

We analyze decoherence and objectivization processes in spin-spin models for arbitrary spins. We first derive the most general analytic form of the decoherence factor in the measurement limit, where the interaction Hamiltonian dominates the rest. We then analyze thermal environments and derive exact, analytic formulas for both the decoherence factor and the state fidelity of post-interaction environment states. This allows to analyze the objectivization process of the state of the central spin during the interaction. We do so using, so called, Spectrum Broadcast Structures (SBS), which are specific multipartite quantum states encoding a certain operation notion of objectivity. We analyze analytically (for short times) and numerically how higher spin influences the efficiency of decoherence and objectivization processes. As expected, the higher the spin of the environment, the more efficient decoherence and objectivization become. This work is a generalization of previous studies, limited to spin-$1/2$ systems only, and we hope will be useful in future objectivity experiments.