Consistent histories of systems and measurements in spacetime

TL;DR

This paper develops a relativistic consistent histories framework for quantum systems and measurements, incorporating Zurek's einselection and envariance to justify Born's rule within a universe-wide, no-collapse interpretation.

Contribution

It introduces a model of measurement processes in relativistic quantum histories and provides a justification for Born's rule using envariance and einselection.

Findings

A relativistic model of systems and measurements in quantum histories.

Application of Zurek's concepts to justify Born's rule in a cosmological context.

Integration of measurement processes within a spacetime path formalism.

Abstract

Traditional interpretations of quantum theory in terms of wave function collapse are particularly unappealing when considering the universe as a whole, where there is no clean separation between classical observer and quantum system and where the description is inherently relativistic. As an alternative, the consistent histories approach provides an attractive "no collapse" interpretation of quantum physics. Consistent histories can also be linked to path-integral formulations that may be readily generalized to the relativistic case. A previous paper described how, in such a relativistic spacetime path formalism, the quantum history of the universe could be considered to be an eignestate of the measurements made within it. However, two important topics were not addressed in detail there: a model of measurement processes in the context of quantum histories in spacetime and a justification for why the probabilities for each possible cosmological eigenstate should follow Born's rule. The present paper addresses these topics by showing how Zurek's concepts of einselection and envariance can be applied in the context of relativistic spacetime and quantum histories. The result is a model of systems and subsystems within the universe and their interaction with each other and their environment.