# IQIM Postdoctoral and Graduate Student Seminar

Tuesday, October 11, 2022
3:00pm to 4:00pm
Annenberg 105
Cosmology from the vacuum
Stefano Antonini, University of Maryland,

Joint HET/IQIM Seminar

Note special time and location: talk begins at 3 pm in 105 Annenberg

Abstract: I will outline a recent proposal (2203.11220,2206.14821) for a holographic description of negative $\Lambda$ cosmologies in holography. The microscopic Euclidean theory involves two 3D holographic CFTs coupled by non-holographic auxiliary 4D degrees of freedom on a strip. The bulk dual Euclidean path integral is dominated by a 4D Euclidean wormhole with two asymptotic AdS boundaries coupled by the non-gravitational auxiliary theory. Two different slicings of the microscopic Euclidean path integral are possible. They correspond to two slicings of the Euclidean wormhole, defining two different Lorentzian spacetimes related by double analytic continuation. The first one is a Big Bang - Big Crunch FLRW cosmological universe; the second one is an AdS eternal traversable wormhole. I will describe the relationship between cosmological observables and observables in the traversable wormhole geometry. This "slicing duality" allows one to probe the cosmological universe using the usual AdS/CFT dictionary even though the cosmology has no asymptotic boundary. Finally, I will comment on the phenomenological viability of these models.

Attendees joining in person must demonstrate that they comply with Caltech's vaccination requirements (present Caltech ID or AWS ID or vaccination and booster confirmation).