Probing de Sitter from the horizon

Abstract

In a QFT on de Sitter background, one can study correlators between fields pushed to the future and past horizons of a comoving observer. This is a neat probe of the physics in the observer's causal diamond (known as the static patch). We use this observable to give a generalization of the quasinormal spectrum in interacting theories, and to connect it to the spectral density that appears in the Källén-Lehmann expansion of dS correlators. We also introduce a finite-temperature effective field theory consisting of free bulk fields coupled to a boundary. In matching it to the low frequency expansion of correlators, we find positivity constraints on the EFT parameters following from unitarity.

24 pages, 3 figures

References in corpus (4)

• Causality, Analyticity and an IR Obstruction to UV Completion
• Stochastic Inflation at NNLO
• Scattering in the static patch of de Sitter space
• Integrable Field Theories and Their CCFT Duals

Cited by in corpus (2)

• The graviton four-point function in de Sitter space
• Real-time observables in de Sitter thermodynamics