2026-09-21T11:12:00Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/16725 2023-07-10 col_2142_5131 col_2142_14807 com_2142_5130 com_2142_14806 com_2142_8903

Wandelt, Benjamin D. Wandelt, Benjamin D. Fields, Brian D. Gammie, Charles F. Sutton, Edmund C. Khatri, Rishi 2010-08-20T17:56:02Z 2010-08-20T17:56:02Z 2010-08-20T17:56:02Z 2010-08 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. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-06-30T21:11:01Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 Khatri_Rishi.tar.gz: 912814 bytes, checksum: 588c9d0ff4e187f36d8f79a5b15d6b0f (MD5) Khatri_Rishi.pdf: 1840921 bytes, checksum: 6eaf269d30284b41ff3866f5162dc0ab (MD5) Made available in DSpace on 2010-08-20T17:56:02Z (GMT). No. of bitstreams: 3 Khatri_Rishi.tar.gz: 912814 bytes, checksum: 588c9d0ff4e187f36d8f79a5b15d6b0f (MD5) Khatri_Rishi.pdf: 1840921 bytes, checksum: 6eaf269d30284b41ff3866f5162dc0ab (MD5) license.txt: 4062 bytes, checksum: c938424d263f572c2bac7b54ba0caafd (MD5) http://hdl.handle.net/2142/16725 en Copyright 2010 by Rishi Khatri. Physical Cosmology Early Universe Fundamental Constants 21-cm Cosmology Cosmic Microwave Background Second Order Perturbation Theory Cosmic Strings Fundamental physics from observations of the early universe Astronomy 1430 Astronomy 0333 University of Illinois at Urbana-Champaign Dissertation Ph.D. PHD:Astronomy -UIUC 10KS0333PHD