IAS Quantum Aspects of Black Holes Group Meeting

Abstract: In the context of inflationary cosmology, a natural question concerns its initial conditions (what precedes inflation itself). The Hartle–Hawking (no-boundary) and Vilenkin (tunneling) proposals face complementary paradoxes and can lead to predictions that are in tension with observations. At the same time, theories of quantum gravity are better understood in the presence of a negative cosmological constant. I will propose a new type of wavefunction of the universe, characterized by asymptotically AdS boundary conditions in the far (Euclidean) past. In the semiclassical limit, this wavefunction is described by a Euclidean (half-)wormhole geometry whose analytic continuation to Lorentzian signature gives rise to an expanding universe. Within this framework, the aforementioned puzzles can be absent. I will describe some examples in which such geometries are classical saddles of the gravitational path integral.