Rationale for a Correlated Worldline Theory of Quantum Gravity

TL;DR

This paper proposes a novel correlated worldline theory of quantum gravity where gravitational correlations between paths cause a breakdown of quantum superposition for large masses, leading to classical behavior at accessible energy scales.

Contribution

It introduces a unique, parameter-free formulation of quantum gravity based on gravitational correlations between worldlines, with a focus on the dynamics of single particles.

Findings

Gravitational correlations cause quantum trajectory bunching.

The theory predicts a rapid transition from quantum to classical behavior for large masses.

Calculations of physical quantities demonstrate the theory's applicability.

Abstract

It is argued that gravity should cause a breakdown of quantum mechanics, at low energies, accessible to table-top experiments. It is then shown that one can formulate a theory of quantum gravity in which gravitational correlations exist between worldline or worldsheet paths, for the particle or field of interest. Using a generalized equivalence principle, one can give a unique form for the correlators, yielding a theory with no adjustable parameters. A key feature of the theory is the "bunching" of quantum trajectories caused by the gravitational correlations - this is {\it not} a decoherence or a "collapse" mechanism. This bunching causes a breakdown of the superposition principle for large masses, with a very rapid crossover to classical behaviour at an energy scale which depends on the physical structure of the object. Formal details, and applications of the theory, are kept to a minimum in this paper; but we show how physical quantities can be calculated, and give a detailed discussion of the dynamics of a single particle.