Large Grants
    - Introduction
    - Awardees
Mini-Grants
    - Introduction
    - Winners
 
Previous Programs

2016 Physics of the Observer
2016 Awardees

2015 The Physics of What Happens
2015 Awardees

2013 Physics of Information
2013 Awardees

2010 The Nature of Time
2010 Awardees

2008 Foundational Questions in Physics and Cosmology
2008 Awardees

2006 Foundational Questions in Physics and Cosmology
2006 Awardees

Dr. Alexander Vilenkin
Tufts University

Co-Investigators

Jaume Garriga, Universitat de Barcelona

Project Title

The Measure Problem in the Inflationary Multiverse

Project Summary

Recent developments in cosmology suggest that much of the universe is in a state of explosive, accelerated expansion, called inflation. We live in a finite "bubble" where inflation has ended, and other bubbles with diverse properties are constantly being formed. All possible events will happen an infinite number of times in such an eternally inflating "multiverse." Unless we learn how to compare these infinities, we will not be able to make any predictions at all. This is known as "the measure problem''. Some of the proposed probability measures predict that "Boltzmann brains'' - hallucinating disembodied brains appearing as quantum fluctuations - greatly outnumber regular observers. We shall investigate how this and other paradoxes can be used to restrict the set of possible measures. We shall also explore how the probability measure can be derived from the fundamental theory, such as quantum gravity. Another direction of the proposed research is the study of bubble collisions. The most spectacular observational test of the multiverse scenario would be a direct observation of a collision of our bubble with another one. We shall investigate observational signatures of such a collision and the probability for us to be close enough to detect one.



Back to List of Awardees  
Please enter your e-mail address:

Note: Joining the FQXi mailing list does not give you a login account or constitute membership in the organization.