Events

Quantum Mechanics of the Hartle-Hawking State

The no-boundary state in de Sitter offers a compelling framework for specifying the initial conditions of our universe. Many (but famously not all) features of the state agree beautifully with empirical observations and have served as a foundation for initial conditions in inflationary cosmology. We explore its relation to entropy puzzles in de Sitter spacetimes. We then compute the norm of the no-boundary state and show that the contributions from geometries with spherical spatial slices, including the Hartle-Hawking geometry and fluctuations around it, vanish to all loops in perturbation theory. We then discuss the resulting implications for theoretical cosmology.

Zoom

Monday, February 2, 2026 9:30 AM

Inperson
BHI Conference Room