Nonunitary Newtonian Gravity

TL;DR

This paper explores how a stable version of higher-derivative gravity transitions from quantum to classical behavior around 10^{11} protons and predicts nonunitary evolution leading to thermalization in closed systems.

Contribution

It introduces a stable realization of higher-derivative gravity and analyzes its Newtonian limit, revealing a sharp quantum-classical transition and nonunitary state evolution.

Findings

Transition from wave-like to classical behavior at 10^{11} protons.

Nonunitary evolution leads to thermal equilibrium in closed systems.

Provides a framework connecting gravity with quantum decoherence.

Abstract

It is shown that the Newtonian limit of a stable realization of HD gravity leads to a sharp transition, around 10^{11} proton masses, from the wavelike properties of microscopic particles to the classical behaviour of macroscopic bodies. Besides, due to nonunitarity, a pure state is expected to evolve into a microcanonical ensamble leading to thermal equilibrium even for truly closed systems.