Some Applications of Open Effective Field Theories to Gravitating Quantum Systems

Abstract

Open Effective Field Theories are a class of Effective Field Theories (EFTs) built using ideas from open quantum systems in which a measured sector (the system) interacts with an unmeasured sector (the environment). It is argued that Open EFTs are useful tools for any situation in which a quantum system couples to a gravitational background with an event horizon. The main reason for this is that for any EFT of gravity one generically expects perturbation theory to breakdown at late times (when interactions with the background persist indefinitely). It is shown that the tools of Open EFTs allow one to resum late-time perturbative breakdowns in order to make reliable late time predictions (without resorting to solving the dynamics exactly). To build evidence of their usefulness to these types of gravitational problems, Open EFT approximation methods are applied to two toy models relating to black hole physics.