Principles for a Distinguished Global Vacuum: Entropy and the Vacuum State in Causal Set Theory

TL;DR

This paper investigates the Sorkin-Johnston vacuum in causal set theory, demonstrating it as the unique global vacuum candidate based on principles linking entropy and field states.

Contribution

It establishes the Sorkin-Johnston vacuum as the sole candidate for the global vacuum in causal set theory under natural assumptions.

Findings

Sorkin-Johnston vacuum is uniquely determined by entropy principles.

The vacuum state aligns with natural assumptions on field space.

The study clarifies the relation between entropy and vacuum selection in causal sets.

Abstract

Using the framework of real scalar field theory on causal sets, the intimate relation of the Sorkin-Johnston vacuum to entropic purity is elucidated. It is shown that taking a set of sensible principles, and the most natural assumption on the space of fields, leaves the Sorkin-Johnston state as the only candidate for the global vacuum of a quasifree theory.