The no-boundary wave function for loop quantum cosmology

TL;DR

This paper integrates the no-boundary wavefunction with loop quantum cosmology, showing quantum geometry effects relax initial condition restrictions and expand the space of inflationary universe solutions.

Contribution

It combines the no-boundary proposal with loop quantum cosmology, revealing quantum effects that ease initial condition constraints and promote inflation.

Findings

Quantum geometry regularizations relax slow-roll potential restrictions.

Quantum effects expand initial conditions for inflation.

Singularity resolution is linked to broader initial state possibilities.

Abstract

Proposing smooth initial conditions is one of the most important tasks in quantum cosmology. On the other hand, the low-energy effective action, appearing in the semiclassical path integral, can get nontrivial quantum corrections near classical singularities due to specific quantum gravity proposals. In this article, we combine the well-known no-boundary proposal for the wavefunction of the universe with quantum modifications coming from loop quantum cosmology (LQC). Remarkably, we find that the restriction of a `slow-roll' type potential in the original Hartle-Hawking proposal is considerably relaxed due to quantum geometry regularizations. Interestingly, the same effects responsible for singularity-resolution in LQC also end up expanding the allowed space of smooth initial conditions leading to an inflationary universe.