Magnetic Braneworlds: Cosmology and Wormholes

TL;DR

This paper constructs and analyzes cosmological models and traversable wormholes within braneworld scenarios embedded in AdS${}_5$ spacetimes, revealing their dual descriptions in boundary conformal field theories and exploring their holographic properties.

Contribution

It provides a novel holographic framework connecting braneworld cosmologies, wormholes, and confinement phenomena in boundary CFTs, with explicit dual descriptions and geometric constructions.

Findings

Existence of flat Big Bang-Big Crunch cosmologies in braneworlds.

Construction of traversable wormholes from analytic continuations of AdS black branes.

Holographic duals relate cosmology to excited CFT states and wormholes to ground states.

Abstract

We construct 4D flat Big Bang-Big Crunch cosmologies and Anti-de Sitter (AdS) planar eternally traversable wormholes using braneworlds embedded in asymptotically AdS${}_5$ spacetimes. The background geometries are the AdS${}_5$ magnetic black brane and the magnetically charged AdS${}_5$ soliton, respectively. The two setups arise from different analytic continuations of the same saddle of the gravitational Euclidean path integral, in which the braneworld takes the form of a Maldacena-Maoz Euclidean wormhole. We show the existence of a holographic dual description of this setup in terms of a microscopic Euclidean boundary conformal field theory (BCFT) on a strip. By analyzing the BCFT Euclidean path integral, we show that the braneworld cosmology is encoded in a pure excited state of a CFT dual to a black brane microstate, whereas the braneworld wormhole is encoded in the ground state of the BCFT. The latter confines in the IR, and we study its confining properties using holography. We also comment on the properties of bulk reconstruction in the two Lorentzian pictures and their relationship via double analytic continuation. This work can be interpreted as an explicit, doubly-holographic realization of the relationship between cosmology, traversable wormholes, and confinement in holography, first proposed in arXiv:2102.05057, arXiv:2203.11220.