A finite-resources description of a measurement process and its implications for the "Wigner's Friend" scenario

TL;DR

This paper introduces a finite-resources model of quantum measurement that incorporates resource limitations, providing new insights into the Wigner's Friend scenario by showing how collapse can be viewed as an effective closed-system dynamics.

Contribution

It presents a novel finite-resources framework for quantum measurement, connecting resource limitations to the effective description of collapse and resolving aspects of the Wigner's Friend paradox.

Findings

Measurement collapse emerges as an effective description of closed dynamics.

Finite resources perspective leads to agreement in Wigner's Friend scenario.

Model leverages equilibration and typicality in quantum systems.

Abstract

Quantum mechanics started out as a theory to describe the smallest scales of energy in Nature. After a hundred years of development it is now routinely employed to describe, among others, quantum computers with thousands of qubits. This tremendous progress turns the debate of foundational questions into a technological imperative. In what follows we introduce a model of a quantum measurement process that consistently includes the impact of having access only to finite resources when describing a macroscopic system, like a measurement apparatus. Leveraging modern tools from equilibration of closed systems and typicality, we show how the measurement collapse can be seen as an effective description of a closed dynamics, of which we do not know all its details. Our model is then exploited to address the ``Wigner Friend Scenario'', and we observe that an agreement is reached when both Wigner and his friend acknowledge their finite resources perspective and describe the measurement process accordingly.