# An inflationary cosmology from anti-de Sitter wormholes

**Authors:** Panos Betzios, Olga Papadoulaki  
**arXiv:** [2403.17046](https://arxiv.org/abs/2403.17046)  
**Date:** 2024-03-25  
**Summary page:** https://www.summarizepaper.com/en/paper/2403.17046v1/

## Key points

- Authors Panos Betzios and Olga Papadoulaki propose a novel wavefunction for the universe derived from the Euclidean path integral.
- The new wavefunction includes asymptotically AdS boundary conditions and reveals a unique Euclidean (half)-wormhole geometry with a local maximum of the scale factor at the surface of reflection symmetry.
- Upon analytic continuation to Lorentzian signature, this geometry leads to an expanding universe.
- The Euclidean wormholes establish natural initial conditions for inflation and support prolonged inflationary epochs in the semi-classical Wheeler-DeWitt wavefunction, addressing issues with the no-boundary proposal.
- The asymptotic AdS conditions in the Euclidean past open up avenues for describing inflating cosmologies and their perturbations within holography.
- This innovative approach sheds light on the origins of inflation and offers insights into broader implications of wormhole geometries in understanding cosmic evolution.
- The findings pave the way for further exploration of quantum gravity, cosmology, and holographic principles in elucidating fundamental aspects of our universe's evolution.

## Summary

In their paper titled "An Inflationary Cosmology from Anti-de Sitter Wormholes," authors Panos Betzios and Olga Papadoulaki propose a novel wavefunction for the universe derived from the Euclidean path integral. This new wavefunction incorporates asymptotically $AdS$ boundary conditions and reveals a unique Euclidean (half)-wormhole geometry characterized by a local maximum of the scale factor at the surface of reflection symmetry. Upon analytic continuation to Lorentzian signature, this geometry gives rise to an expanding universe. The authors demonstrate that these Euclidean wormholes establish natural initial conditions for inflation and support a prolonged inflationary epoch in the semi-classical Wheeler-DeWitt wavefunction. This addresses a longstanding issue with the no-boundary proposal. By virtue of the asymptotic $AdS$ conditions in the Euclidean past, these wormholes open up avenues for describing inflating cosmologies and their perturbations within the framework of holography. This innovative approach not only sheds light on the origins of inflation but also offers insights into the broader implications of wormhole geometries in shaping our understanding of cosmic evolution. The findings presented in this study pave the way for further exploration of the interplay between quantum gravity, cosmology, and holographic principles in elucidating fundamental aspects of our universe's evolution.