Observers, alpha parameters, and the Hartle-Hawking state

Abstract: In this talk I will clear up some misunderstandings about the gravitational path integral and quantum gravity in a closed universe. I will explain that there are really three inequivalent versions of the path integral, each of which appears in various applications. For example I will explain why the closed string Hilbert space is not one-dimensional, and also why Coleman's \alpha-parameters do not resolve the black hole information problem. I will explain a connection between recent proposals for using an observer to resolve the one-dimensional Hilbert space problem and the coarse-grained spectral form factor in AdS/CFT, and I will also explain the (nontrivial) relationship between the Hartle-Hawking state and the unique state of holographic cosmology.

HEP - phenomenologyHEP - theorymathematical physics

Audience: researchers in the topic

NHETC Seminar

Series comments: Description: Weekly research seminar of the NHETC at Rutgers University

Livestream link is available on the webpage.