Matthew Johnson

Research Interests

The goal of my research is to understand the fundamental laws of nature through their impact on cosmology. I am primarily a theorist, dabbling in cosmology, field theory, string theory, and gravitation. I also design data analysis algorithms to confront fundamental theory with observations of the Cosmic Microwave Background (CMB) radiation. Here is a sampling of questions that my research aims to answer: How big is the universe? What might lie beyond our observable universe, and how could we confirm or disprove various proposals? What role do the extra dimensions predicted by string theory play in cosmology? Are there new ways of looking at cosmological datasets that could be useful when confronting theories with data? Can computer simulations of the very early universe shed light on it's possible initial conditions and evolution?

Positions Held

• 2012 - present York University and Perimeter Institute, Assistant Professor 2010 - 2012 Perimeter Institute for Theoretical Physics, Postdoctoral Scholar 2007 - 2010 California Institute of Technology, Moore Postdoctoral Scholar

Recent Publications

• Carroll L. Wainwright, Matthew C. Johnson, Hiranya V. Peiris, and Anthony Aguirre, Simulating the universe(s) II: phenomenology of cosmic bubble collisions in full General Relativity, Accepted to JCAP (2014), arXiv: 1407.2950.
• Carroll L. Wainwright, Matthew C. Johnson, Hiranya V. Peiris, Anthony Aguirre, Luis Lehner, and Steven L. Liebling, Simulating the universe(s): from cosmic bubble collisions to cosmological observables with numerical relativity, JCAP 03 030 (2014). arXiv: 1312.1357
• Stephen M. Feeney, Matthew C. Johnson, Jason D. McEwan, Daniel J. Mortlock, Hiranya V. Peiris, Hierarchical Bayesian Detection Algorithm for Early-Universe Relics in the Cosmic Microwave Background, Phys. Rev. D88, 043012 (2013). arXiv: 1210.2725
• Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, Hiranya V. Peiris, A robust constraint on cosmic textures from the cosmic microwave background, Phys.Rev.Lett. 108, 241301 (2012), arXiv: 1203.1928.
• Jason D. McEwen, Stephen M. Feeney, Matthew C. Johnson, Hiranya V. Peiris, Optimal filters for detecting cosmic bubble collisions, Phys.Rev. D85, 103502 (2012), 1202.2861
• Matthew C. Johnson and Jean-Luc Lehners, Cycles in the Multiverse, Phys.Rev. D85, 103509 (2012), arXiv: 1112.3360.
• Matthew C. Johnson, Hiranya V. Peiris, Luis Lehner, Determining the outcome of cosmic bubble collisions in full General Relativity, Phys.Rev. D85, 083516 (2012), arXiv: 1112.4487.
• Anthony Aguirre, Sean M. Carroll, Matthew C. Johnson, Out of equilibrium: understanding cosmological evolution to lower-entropy states, JCAP 1202, 024 (2012), arXiv: 1108.0417.
• Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, Hiranya V. Peiris, First Observational Tests of Eternal Inflation: Analysis Methods and WMAP 7-Year Results, Phys. Rev. D 84, 043507 (2011), arXiv: 1012.3667.
• Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, Hiranya V. Peiris, First Observational Tests of Eternal Inflation, Phys. Rev. Lett. 107, 071301 (2011), arXiv: 1012.1995.

Seminars

• Early Universe Cosmology, CAP Congress
• Simulating the Universe(s), Canadian Conference on General Relativity and Relativistic Astrophysics
• Simulating the Universe(s), Imperial College London
• Eternal Inflation, University of Waterloo
• Eternal Inflation, Quantum Gravity and Fundamental Cosmology Workshop, Albert Einstein Institute, Potsdam Germany
• Searching for early-universe relics in the CMB, McGill University
• PIRSA:14080035, 14/15 PSI - Differential Geormetry, 2014-08-28,
• PIRSA:14080034, 14/15 PSI - Differential Geormetry, 2014-08-27,
• PIRSA:14080033, 14/15 PSI - Differential Geormetry, 2014-08-26,
• PIRSA:14080032, 14/15 PSI - Differential Geormetry, 2014-08-25,
• PIRSA:14070025, Searching for Other Universes, 2014-07-14, ISSYP 2014
• PIRSA:14070020, EinsteinPlus 2014 - Cosmology Keynote, 2014-07-08, EinsteinPlus 2014
• PIRSA:14040059, 13/14 PSI - Explorations in Cosmology - Lecture 14, 2014-04-25, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040058, 13/14 PSI - Explorations in Cosmology - Lecture 13, 2014-04-24, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040057, 13/14 PSI - Explorations in Cosmology - Lecture 12, 2014-04-23, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040056, 13/14 PSI - Explorations in Cosmology - Lecture 11, 2014-04-22, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040055, 13/14 PSI - Explorations in Cosmology - Lecture 10, 2014-04-21, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040051, 13/14 PSI - Explorations in Cosmology - Lecture 9, 2014-04-17, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040050, 13/14 PSI - Explorations in Cosmology - Lecture 8, 2014-04-16, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040049, 13/14 PSI - Explorations in Cosmology - Lecture 7, 2014-04-15, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040048, 13/14 PSI - Explorations in Cosmology - Lecture 6, 2014-04-14, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040045, 13/14 PSI - Explorations in Cosmology - Lecture 5, 2014-04-11, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040044, 13/14 PSI - Explorations in Cosmology - Lecture 4, 2014-04-10, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040043, 13/14 PSI - Explorations in Cosmology - Lecture 3, 2014-04-09, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040042, 13/14 PSI - Explorations in Cosmology - Lecture 2, 2014-04-08, 13/14 PSI - Explorations in Cosmology
• PIRSA:14040041, 13/14 PSI - Explorations in Cosmology - Lecture 1, 2014-04-07, 13/14 PSI - Explorations in Cosmology
• PIRSA:14010101, Simulating the Universe(s), 2014-01-14, Cosmology & Gravitation
• PIRSA:13070058, Quantum Cosmology - 3, 2013-07-23, Loops 13
• PIRSA:13070029, Searching for Other Universes, 2013-07-08, ISSYP 2013
• PIRSA:13040080, 12/13 PSI - Explorations in Cosmology Lecture 15, 2013-04-26, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040079, 12/13 PSI - Explorations in Cosmology Lecture 14, 2013-04-25, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040078, 12/13 PSI - Explorations in Cosmology Lecture 13, 2013-04-24, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040077, 12/13 PSI - Explorations in Cosmology Lecture 12, 2013-04-23, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040076, 12/13 PSI - Explorations in Cosmology Lecture 11, 2013-04-22, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040073, 12/13 PSI - Explorations in Cosmology Lecture 10, 2013-04-19, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040072, 12/13 PSI - Explorations in Cosmology Lecture 9, 2013-04-18, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040071, 12/13 PSI - Explorations in Cosmology Lecture 8, 2013-04-17, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040070, 12/13 PSI - Explorations in Cosmology Lecture 7, 2013-04-16, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040069, 12/13 PSI - Explorations in Cosmology Lecture 6, 2013-04-15, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040066, 12/13 PSI - Explorations in Cosmology Lecture 5, 2013-04-12, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040065, 12/13 PSI - Explorations in Cosmology Lecture 4, 2013-04-11, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040064, 12/13 PSI - Explorations in Cosmology Lecture 3, 2013-04-10, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040063, 12/13 PSI - Explorations in Cosmology Lecture 2, 2013-04-09, 12/13 PSI - Explorations in Cosmology
• PIRSA:13040062, 12/13 PSI - Explorations in Cosmology Lecture 1, 2013-04-08, 12/13 PSI - Explorations in Cosmology
• PIRSA:12100050, 12/13 PSI Researcher Presentation, 2012-10-24, 12/13 PSI Researcher Presentations
• PIRSA:12020144, Feature-finding in the cosmic microwave background, 2012-02-09, Workshop: Computational Methods at Perimeter
• PIRSA:11010114, Observational tests of eternal inflation, 2011-01-25, Cosmology & Gravitation
• PIRSA:09070023, Dynamical compactification from higher dimensional de Sitter space, 2009-07-16, Holographic Cosmology Conference
• PIRSA:06120021, Bubble Nucleation and Eternal Inflation, 2006-12-05, Young Researchers Conference - 2006