Signatures of causality and determinism in a quantum theory of events

TL;DR

This paper introduces a quantum framework for analyzing causality and determinism in events by representing events as joint states, extending superposition principles to events, and applying quantum information measures to spacetime events.

Contribution

It develops a novel quantum approach to model events in spacetime, revealing signatures of causality and extending quantum information tools to temporal correlations.

Findings

Quantum signatures of causality via coherence and correlations.

Deterministic relationships between causally connected events.

Extension of quantum information measures to spacetime events.

Abstract

By representing an event as the joint state of a detector-timer couple that interact with a system, we recover the familiar tensor product structure, used to describe spatially separated systems, in the context of timelike events. Furthermore, with this approach, we extend the superposition principle to the moment of occurrence of events. We then outline quantum signatures of causality that manifest through coherence in the detector state and correlation functions of time operators. Finally, we expand the scope of quantum information theoretic measures of state discrimination and information content, commonly used to characterize spatially separated systems, to events in spacetime. For causally connected events, we illustrate a deterministic relationship between events (akin to spatially entangled physical systems) where observing a previous event (one subsystem), enables us to delineate a later event (the other subsystem).