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Simidzija, Petar

University of British Columbia

We present a model of quantum cosmology based on anti-de Sitter/conformal field theory (AdS/CFT) holography. The spacetimes in our construction are time-symmetric, big-bang/big-crunch cosmologies with a negative cosmological constant 𝚲. In the simplest version of our model the cosmology lives inside a spatially finite bubble within an otherwise empty AdS spacetime. By studying the thermodynamic and geometric properties of this spacetime, we provide evidence that the "bubble of cosmology" spacetime has a well-defined dual CFT description. We also present an upgraded model in which the cosmology is spatially infinite, homogeneous, and isotropic. Although a homogeneous cosmology is not asymptotically AdS and hence cannot be described directly by AdS/CFT, the time-reflection symmetry of the spacetime allows us to perform an analytic continuation, following which the spacetime is an asymptotically AdS Euclidean wormhole. If we assume that the cosmology is spatially flat a second analytic continuation obtains a Lorentzian traversable AdS wormhole. The AdS wormhole spacetimes can be described using holography: they are dual to a pair of three-dimensional CFTs coupled via a four-dimensional theory. We explain how an anomalously large amount of negative energy can support the traversable wormhole, and we begin to populate the holographic dictionary relating observables in the wormhole/cosmology to observables in the microscopic theory. Finally we show that time-dependent scalar fields naturally enable these cosmologies to contain a period of accelerated expansion, suggesting that our 𝚲<0 models could ultimately provide the framework for a fully microscopic description of our Universe.

Text

2024-07-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88729

Physics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/