No-boundary solutions are robust to quantum gravity corrections

Understand

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.