Space and time correlations in quantum histories

TL;DR

This paper explores the formalism of quantum histories to analyze space-time correlations, demonstrating how spatial and temporal entanglement can be characterized and how certain inequalities can be violated within this framework.

Contribution

It introduces a novel approach to treat space and time correlations symmetrically in quantum histories and provides an operational protocol for mapping history states.

Findings

Space and time entanglement can be characterized within the quantum histories framework.

Violations of Leggett-Garg and temporal CHSH inequalities are demonstrated.

A protocol for mapping history states into static system kets is presented.

Abstract

The formalism of generalized quantum histories allows a symmetrical treatment of space and time correlations, by taking different traces of the same history density matrix. We recall how to characterize spatial and temporal entanglement in this framework. An operative protocol is presented, to map a history state into the ket of a static composite system. We show, by examples, how the Leggett-Garg and the temporal CHSH inequalities can be violated in our approach.