Cosmological Correlators in Gravitationally-Constrained De Sitter States
Speaker
Date
Time
Place
Cosmology Hall (Room 7S1)
Abstract
The G_N->0 limit of quantum gravity in de Sitter space is distinct from a nongravitational QFT because the gravitational constraints still force states and observables to be de Sitter invariant. We compute the simplest late-time perturbative observables in this theory and obtain conformally-invariant results. But these observables do not coincide with QFT cosmological correlators in the Hartle-Hawking state. We show that, in the presence of a heavy background state, it is possible to construct a separate class of state-dependent relational observables whose values approximate QFT correlators in the Hartle-Hawking state. This illustrates a key contrast in quantum gravity -- between observables that are microscopically simple and observables whose expectation values in an appropriate background state lead to simple QFT-like correlators.
Biography
Suvrat Raju is a professor at the International Centre for Theoretical Sciences (ICTS) of the Tata Institute of Fundamental Research (TIFR) in Bengaluru, India. He is an expert in quantum gravity and its applications to black holes and cosmology. He received the 2022 Nishina Asia Award for "his original and influential insights into the resolution of the black hole information paradox and the principle of holography in quantum gravity" and the 2019 ICTP Prize for "for new insights into the holographic description of black-hole interiors, for clarifying the nature of subtle non-local effects in quantum gravity, and for contributions to the study of the AdS/CFT correspondence."