{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/16725"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/16725","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Fundamental physics from observations of the early universe","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.","abstract_html":"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.","abstract_has_math":false,"creators":["Khatri, Rishi"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Wandelt, Benjamin D.","Fields, Brian D.","Gammie, Charles F.","Sutton, Edmund C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-08-20T17:56:02Z","date_published":"2010-08-20T17:56:02Z","updated_at":"2026-07-22T22:25:09Z","subjects":["Physical Cosmology","Early Universe","Fundamental Constants","21-cm Cosmology","Cosmic Microwave Background","Second Order Perturbation Theory","Cosmic Strings"],"languages":["en"],"rights":["Copyright 2010 by Rishi Khatri."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/16725","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wandelt, Benjamin D.","Fields, Brian D.","Gammie, Charles F.","Sutton, Edmund C."]},{"key":"dc:creator","label":"Author","values":["Khatri, Rishi"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2010-08-20T17:56:02Z","2010-08"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physical Cosmology","Early Universe","Fundamental Constants","21-cm Cosmology","Cosmic Microwave Background","Second Order Perturbation Theory","Cosmic Strings"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2010 by Rishi Khatri."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/16725"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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). 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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)"],"dc:identifier":["http://hdl.handle.net/2142/16725"],"dc:language":["en"],"dc:rights":["Copyright 2010 by Rishi Khatri."],"dc:subject":["Physical Cosmology","Early Universe","Fundamental Constants","21-cm Cosmology","Cosmic Microwave Background","Second Order Perturbation Theory","Cosmic Strings"],"dc:title":["Fundamental physics from observations of the early universe"],"thesis:degree_discipline":["Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:09Z"}