Nonlinear Quantum Cosmology

TL;DR

This paper investigates how nonlinear corrections to the Wheeler-deWitt equation influence quantum cosmology, revealing mechanisms for universe creation and bounces that could resolve classical singularities.

Contribution

It introduces a nonlinear modification to quantum cosmology equations and demonstrates its effects on universe creation and singularity avoidance.

Findings

Nonlinearity creates a barrier that enables universe tunneling from nothing.

Nonlinearity induces a bounce, preventing collapse to zero size.

Results are consistent within leading-order perturbation theory.

Abstract

We study the effects of an information-theoretically motivated nonlinear correction to the Wheeler-deWitt equation in the minisuperspace scheme for flat, $k=0$, Friedmann-Robertson-Walker (FRW) universes. When the only matter is a cosmological constant, the nonlinearity can provide a barrier that screens the original Big Bang, leading to the quantum creation of a universe through tunneling just as in the $k=1$ case. When the matter is instead a free massless scalar field, the nonlinearity can again prevent a contracting classical universe from reaching zero size by creating a bounce. Our studies here are self-consistent to leading order in perturbation theory for the nonlinear effects.