# Analyzing Cosmic Bubble Collisions

@article{Gobbetti2012AnalyzingCB, title={Analyzing Cosmic Bubble Collisions}, author={Roberto Gobbetti and Matthew Kleban}, journal={Journal of Cosmology and Astroparticle Physics}, year={2012}, volume={2012}, pages={025-025} }

We develop a set of controlled, analytic approximations to study the effects of bubble collisions on cosmology. We expand the initial perturbation to the inflaton field caused by the collision in a general power series, and determine its time evolution during inflation in terms of the coefficients in the expansion. In models where the observer's bubble undergoes sufficient slow-roll inflation to solve the flatness problem, in the thin wall limit only one coefficient in the expansion is relevant…

## 23 Citations

Cosmic bubble and domain wall instabilities III: The role of oscillons in three-dimensional bubble collisions

- Physics
- 2015

We study collisions between pairs of bubbles nucleated in an ambient false vacuum. For the first time, we include the effects of small initial (quantum) fluctuations around the instanton profiles…

Cosmic bubble and domain wall instabilities I: parametric amplification of linear fluctuations

- Physics
- 2014

This is the first paper in a series where we study collisions of nucleated bubbles taking into account the effects of small initial (quantum) fluctuations in a fully 3+1-dimensional setting. In this…

Simulating the universe(s) II: phenomenology of cosmic bubble collisions in full General Relativity

- Physics
- 2014

Observing the relics of collisions between bubble universes would provide direct evidence for the existence of an eternally inflating Multiverse; the non-observation of such events can also provide…

Simulating the universe(s): from cosmic bubble collisions to cosmological observables with numerical relativity

- Physics
- 2014

The theory of eternal inflation in an inflaton potential with multiple vacua predicts that our universe is one of many bubble universes nucleating and growing inside an ever-expanding false vacuum.…

Simulating the Universe(s) III: Observables for the full bubble collision spacetime

- Physics
- 2015

This is the third paper in a series establishing a quantitative relation between inflationary scalar field potential landscapes and the relic perturbations left by the collision between bubbles…

Multiple cosmic collisions and the microwave background power spectrum

- Physics
- 2013

Collisions between cosmic bubbles of different vacua are a generic feature of false vacuum eternal inflation scenarios. While previous studies have focused on the consequences of a single collision…

Searches for other vacua. Part I. Bubbles in our universe

- PhysicsJournal of High Energy Physics
- 2019

Abstract
We discuss models in which vacua other than our own can be directly observed in the present universe. Models with density-dependent vacuum structure can give rise to ‘non-lethal’-vacua:…

Nonlinear Intermittent Field Dynamics in the Early Universe

- Physics
- 2015

We explore nonequilibrium dynamics of inhomogeneous nonlinearly interacting scalar fields in several cosmological settings. In particular, we explore the effects of (initially small) asymmetric…

Gravity waves from cosmic bubble collisions

- Physics
- 2013

Our local Hubble volume might be contained within a bubble that nucleated in a false vacuum with only two large spatial dimensions. We study bubble collisions in this scenario and find that they…

Observable Signatures of a Classical Transition

- Physics
- 2015

Eternal inflation arising from a potential landscape predicts that our universe is one realization of many possible cosmological histories. One way to access different cosmological histories is via…

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