Implementation of classical communication in a quantum world

TL;DR

This paper explores how classical communication in quantum systems, specifically LOCC observations, can be implemented through Hamiltonian dynamics, emphasizing the role of POVMs and entanglement in the process.

Contribution

It demonstrates that LOCC observations require predefined POVMs and can be understood via system-observer entanglement, extending the understanding of quantum measurement dynamics.

Findings

LOCC observations cannot be explained by decoherence alone.

Implementation of LOCC involves predefined POVMs agreed upon by observers.

Classical information transfer can be modeled through system-observer entanglement.

Abstract

Observations of quantum systems carried out by finite observers who subsequently communicate their results using classical data structures can be described as "local operations, classical communication" (LOCC) observations. The implementation of LOCC observations by the Hamiltonian dynamics prescribed by minimal quantum mechanics is investigated. It is shown that LOCC observations cannot be described using decoherence considerations alone, but rather require the \textit{a priori} stipulation of a positive operator-valued measure (POVM) about which communicating observers agree. It is also shown that the transfer of classical information from system to observer can be described in terms of system-observer entanglement, raising the possibility that an apparatus implementing an appropriate POVM can reveal the entangled system-observer states that implement LOCC observations.