No-boundary solutions are robust to quantum gravity corrections

TL;DR

This paper demonstrates that the no-boundary proposal for the universe's initial conditions remains robust when quantum gravity corrections are included, supporting its consistency within a broader theoretical context.

Contribution

It provides explicit calculations showing that quantum gravity corrections do not eliminate no-boundary solutions, confirming their stability and consistency.

Findings

No-boundary solutions are modified but not destroyed by quantum corrections.

Quantum gravity corrections involving higher curvature terms are compatible with the no-boundary proposal.

Examples from string theory support the robustness of these solutions.

Abstract

The no-boundary proposal is a theory of the initial conditions of the universe formulated in semi-classical gravity, and relying on the existence of regular (complex) solutions of the equations of motion. We show by explicit computation that regular no-boundary solutions are modified, but not destroyed, upon inclusion of expected quantum gravity corrections that involve higher powers of the Riemann tensor as well as covariant derivatives thereof. We illustrate our results with examples drawn from string theory. Our findings provide a crucial self-consistency test of the no-boundary framework.