Semiclassical world is one of infinite many cloneworlds in common spacetime

TL;DR

This paper explores a model of many interacting quantum clones of the universe, deriving semiclassical equations and comparing different approaches to correlated cloneworlds, providing new insights into quantum gravity and semiclassical gravity.

Contribution

It introduces a novel model of infinitely many quantum clones interacting via scaled gravity, deriving semiclassical Einstein equations and clarifying differences with previous correlated worldline proposals.

Findings

Derived semiclassical Einstein equations for cloneworlds.

Provided an alternative proof of the Schrödinger-Newton equation.

Compared cloneworlds with Stamp's correlated worldlines, highlighting key differences.

Abstract

We consider $N$ clones of the quantized world, interacting with each other via quantum gravity, coupled by the downscaled Newton constant $G/N$. In the limit $N\rightarrow\infty$, we obtain the semiclassical Einstein equation for every single cloneworld. In the non-relativistic limit, De Filippo had already obtained the semiclassical Schr\"odinger-Newton equation, we present an alternative elementary proof. In the general relativistic case we complete the semi-finished derivation of Hartle and Horowitz. We compare our simple correlated cloneworlds with Stamp's more complicated proposal of correlated worldlines and show why they differ despite the conceptual similarity.