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Investigations into the Conditions Necessary for Stochastic Eternal Inflation


Kuns, Kevin Aaron (2012) Investigations into the Conditions Necessary for Stochastic Eternal Inflation. Senior thesis (Major), California Institute of Technology. doi:10.7907/VA85-YW36.


Theories of cosmological inflation, an early exponential expansion of the universe, have solved the horizon, flatness, and monopole problems in addition to successfully predicting properties of the fluctuations in the cosmic microwave background. Many of these theories have the property, known as eternal inflation, where inflation never ends everywhere at the same time and where there are always regions of exponentially expanding inflating space. The details of inflation are not known at this time and it would be interesting to estimate how generic eternal inflation is in the space of possible inflaton potentials. Of the several ways that inflation can be eternal, we focus here on the one, known as stochastic eternal inflation, where inflation is prevented from ending everywhere by quantum fluctuations in the inflaton field exceeding its classical motion. We argue that the conditions currently used to classify a trajectory as stochastically eternal are inadequate for general trajectories where the inflaton field may classically have a large velocity or be moving up its potential and are therefore illsuited to studying how generic stochastic eternal inflation is. We propose an improved condition that takes these possibilities into account as well as more accurately calculating the quantum fluctuations using a perturbative Langevin method developed elsewhere. We investigate this condition in specific inflaton potentials and find examples where this condition deviates significantly from the one usually used in addition to finding examples where the mechanisms for eternal inflation are seemingly met even though space is not inflating.

Item Type:Thesis (Senior thesis (Major))
Subject Keywords:Physics
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Awards:D.S. Kothari Prize in Physics, 2012.
Thesis Availability:Not set
Research Advisor(s):
  • Carroll, Sean M.
Thesis Committee:
  • None, None
Defense Date:8 May 2012
Record Number:CaltechTHESIS:02132018-124239126
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10710
Deposited By: Joy Painter
Deposited On:14 Feb 2018 00:14
Last Modified:07 Nov 2022 23:11

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