Fundamental physics from observations of the early universe

Khatri, Rishi

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https://hdl.handle.net/2142/16725 Copy

Description

Title

Fundamental physics from observations of the early universe

Author(s)

Khatri, Rishi

Issue Date

2010-08-20T17:56:02Z

Director of Research (if dissertation) or Advisor (if thesis)

Wandelt, Benjamin D.

Doctoral Committee Chair(s)

Wandelt, Benjamin D.

Committee Member(s)

• Fields, Brian D.
• Gammie, Charles F.
• Sutton, Edmund C.

Department of Study

Astronomy

Discipline

Astronomy

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Physical Cosmology
• Early Universe
• Fundamental Constants
• 21-cm Cosmology
• Cosmic Microwave Background
• Second Order Perturbation Theory
• Cosmic Strings

Abstract

The current experiments like Planck and future CMB, 21-cm and other large scale structure surveys will enable cosmology to answer some of the fundamental questions in physics. The linear perturbation theory may not be accurate enough to interpret the observations from Planck and future CMB experiments. Second order effects may in particular be important in constraining the non-Gaussianity in the initial conditions of the Universe. Inhomogeneities in recombination and reionization amplify the perturbations in the underlying matter density and the resulting second order effects may be important. I calculate the bispectrum due to these second order effects and find that they are not an important source of confusion with the primordial non-Gaussianities. 21-cm observations of the era between the recombination and reionization will provide a wealth of data in the future. I study what we can learn about fundamental physics from these observations. In particular I calculate the constraints we might get from the future data on the existence and properties of cosmic strings, a prediction of GUT and superstring theories, and the variation of fundamental constants.

Graduation Semester

2010-08

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http://hdl.handle.net/2142/16725

Copyright and License Information

Copyright 2010 by Rishi Khatri.

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