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Mark Wyman

Mark Wyman's picture
University of Chicago - Dept. of Astronomy and Astrophysics

Area of Research:
Cosmology
Website: http://www.markcwyman.com
Phone: x7511

Research Interests

I am working on inflation, large scale structure in modified gravity models, and cosmic superstrings. Within inflation, I am studying DBI inflation in particular, with conclusions that generalize to other k-inflation / k-essence theories. After studying both tunneling and eternal inflation for such theories, I am now fleshing out a mechanism that generates these kinds of theories as a low energy effective theory coming from general multi-field models where the fields have kinetic terms that are dependent on the values of other fields, such as occurs in supergravity models of closed string moduli. A long term goal is a better understanding of large perturbations in DBI / k-essence models. The modified gravity model I am studying is inspired by the Dvali-Gabadadze-Porrati brane-world model; in more mundane terms, it is a phenomenologically viable modification of gravity with a very light, but massive, graviton. My work is concerned with how large scale structure develops in this model. I am using N-body, particle-mesh codes to study this: first, on a short time scale, using a modified version of the Newtonian Poisson equation, followed by a more comprehensive solution of the full non-linear differential equations that describe the extra scalar degree of freedom that a massive graviton must exhibit. I will compare these results to galaxy survey data and other cosmological observations to place limits on these models. Finally, I am continuing to study the distinctive phenomenology of cosmic superstrings. Their contributions to the small angular scale power and B-mode polarization of the CMB could be seen within the next couple of years. In the meantime, I am working out their effect on the 21 cm radiation that will eventually be the richest resource for observational data.

Positions Held

  • 2006-2010 Perimeter Institute Postdoctoral Fellow. 2010- Postdoctoral Fellow, University of Chicago

Awards

  • NASA Graduate Fellowship
  • NSF Graduate Fellowship
  • Phi Kappa Phi Graduate Fellowship

Recent Publications

  • Enhanced Peculiar Velocities in Brane-Induced Gravity, M. Wyman and J. Khoury, arxiv: 1004.2046
  • Correlations between 21 cm Radiation and the CMB from Active Sources, arxiv: 1003.2214
  • N-Body Simulations of DGP and Degravitation Theories, Justin Khoury, Mark Wyman, Phys. Rev. D 80, 064023 (2009), arxiv: 0903.1292
  • Andrew J. Tolley, Mark Wyman, Stochastic tunneling for strongly non-Gaussian inflationary theories, JCAP 10 (2009) 006, arxiv: 0809.1100
  • Levon Pogosian, S.-H. Henry Tye, Ira Wasserman, Mark Wyman, Cosmic Strings as the Source of Small-Scale Microwave Background Anisotropy, JCAP02(2009)013, arxiv: 0804.0810
  • Andrew J. Tolley, Mark Wyman, Stochastic Inflation Revisited: Non-Slow Roll Statistics and DBI Inflation, JCAP 0804:028,2008, arxiv: 0801.1854
  • Levon Pogosian, Mark Wyman, B-modes from Cosmic Strings, Phys.Rev.D77:083509,2008, arxiv: 0711.0747
  • Diana Battefeld, Thorsten Battefeld, Daniel H. Wesley, Mark Wyman, Magnetogenesis from Cosmic String Loops, JCAP 02 (2008) 001, arxiv: 0708.2901
  • Cosmic Necklaces from String Theory, Louis Leblond, Mark Wyman, arxiv: 701427, Phys.Rev.D75:123522,2007
  • The Gelaton Scenario: Equilateral non-Gaussianity from multi-field dynamics, Andrew J. Tolley, Mark Wyman, arxiv: 0910.1853
  • N-Body Simulations of DGP and Degravitation Theories, Justin Khoury, Mark Wyman, arxiv: 0903.1292
  • R. Myers and M. Wyman, {\it Cosmic Superstrings}, chapter in book, {\bf String Cosmology} (2009) Wiley / VCH, edited by Johanna Erdmenger.

Seminars

  • The Gelaton Scenario: CITA, Cornell University
  • Enhanced Peculiar Velocities from Brane-Induced Gravity: University of Chicago / KICP (conference), NYU
  • N-body Simulations of DGP and Degravitation: Cambridge / DAMTP, Simon Fraser University, CITA
  • Beyond Vanilla Cosmology [Colloquium]: UW-Milwaukee, Royal Military College of Canada, Cornell University
  • Cosmic strings: B-modes, magnetic field generation, and WMAP limits: U Penn, KICP / Chicago, Fermilab, McGill University, CITA, Tufts, Penn State, College of William and Mary, Cornell
  • Stochastic Inflation Revisited: Syracuse University, U Penn, Princeton, Delaware, Columbia