Extended Rindler Spacetime and a New Multiverse Structure

TL;DR

This paper explores a new multiverse structure emerging from the analyticity properties of quantum fields in extended Rindler spacetime, revealing connections between universes and implications for information flow in black hole geometries.

Contribution

It introduces a novel multiverse framework based on analyticity of quantum fields in extended Rindler space, linking multiple universes through branch cuts and analyzing information transfer.

Findings

Quantum fields in extended Rindler space form an infinite stack of universes.

In the absence of interactions, no information flows between these universes.

Black hole spacetimes enable information loss via flow to other universes through additional branch points.

Abstract

This is the first of a series of papers in which we use analyticity properties of quantum fields propagating on a spacetime to uncover a new multiverse geometry when the classical geometry has horizons and/or singularities. The nature and origin of the multiverse idea presented in this paper, that is shared by the fields in the standard model coupled to gravity, is different from other notions of a multiverse. Via analyticity we are able to establish definite relations among the universes. In this paper we illustrate these properties for the extended Rindler space, while black hole spacetime and the cosmological geometry of mini-superspace (see Appendix B) will appear in later papers. In classical general relativity, extended Rindler space is equivalent to flat Minkowski space; it consists of the union of the four wedges in (u,v) light-cone coordinates as in Fig.(1). In quantum mechanics, the wavefunction is an analytic function of (u,v) that is sensitive to branch points at the horizons u=0 or v=0, with branch cuts attached to them. The wavefunction is uniquely defined by analyticity on an infinite number of sheets in the cut analytic (u,v) spacetime. This structure is naturally interpreted as an infinite stack of identical Minkowski geometries, or universes, connected to each other by analyticity across branch cuts, such that each sheet represents a different Minkowski universe when (u,v) are analytically continued to the real axis on any sheet. We show in this paper that, in the absence of interactions, information doesn't flow from one Rindler sheet to another. By contrast, for an eternal black hole spacetime, which may be viewed as a modification of Rindler that includes gravitational interactions, analyticity shows how information is lost due to a flow to other universes, enabled by an additional branch point and cut due to the black hole singularity.