{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/127257"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/127257","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Studies of quadratic gravity with chaos and instability","abstract":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms","abstract_html":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms","abstract_has_math":false,"creators":["Deich, Alexander"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Yunes, Nicolás","Gammie, Charles","Noronha-Hostler, Jacquelyn","Filippini, Jeffrey"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2024,"date_issued":"2024-12-05","date_published":"2024-12-05","updated_at":"2026-07-22T22:25:03Z","subjects":["Gravity","Black Holes","Chaos","Vlbi","Ligo","Lisa","Lyapunov","Poincare"],"languages":["en","eng"],"rights":["Copyright 2024 Alexander Deich"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/127257","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Yunes, Nicolás","Gammie, Charles","Noronha-Hostler, Jacquelyn","Filippini, Jeffrey"]},{"key":"dc:creator","label":"Author","values":["Deich, Alexander"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2024-12-05","2024-12"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"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":["Gravity","Black Holes","Chaos","Vlbi","Ligo","Lisa","Lyapunov","Poincare"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2024 Alexander Deich"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/127257"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms","The student, Alexander Deich, accepted the attached license on 2024-12-02 at 20:39.","The student, Alexander Deich, submitted this Dissertation for approval on 2024-12-02 at 20:46.","This Dissertation was approved for publication on 2024-12-05 at 11:37.","DSpace SAF Submission Ingestion Package generated from Vireo submission #21460 on 2025-03-28 at 14:27:53","From gravitational wave detectors to very long baseline interferometers, experimental relativity is being born. With the promise of troves of data from the space very near black holes, we are at the cusp of having a sharper view of the most extreme gravitational environments than ever before. In addition, the last half- century of theoretical work has provided a trove of potential modifications to the theory of gravity which we might test with the incoming new data. One approach to testing these theories is to look at what the trajectories of test particles can tell us about the underlying theory, and how we might be able to make observations of those particles with current and future instruments. In particular, the extent to which these trajectories exhibit signs of instability and chaos offer a unique, and in principle independent, test of the metrics which govern their motion. In this dissertation, we focus on how we might test two theories of gravity, dynamical-Chern-Simons (dCS), and scalar-Gauss-Bonnet (sGB). We begin with testing to what extent dynamical chaos may present itself in massive test particle trajectories around black holes in these theories. We show that while these theories may permit chaotic orbits, any features are likely too tiny to be detectable in extreme-mass-ratio inspiral (EMRI) signals in near-future detectors. Then, we look at how the spin expansion order of the metrics may impact the precision of calculated observables. We show that for all but the most rapidly spinning black holes, many astrophysical observables may be calculated with only the first half dozen expansion terms. Finally, we investigate how the instability of photon trajectories in black hole solutions may lead to differences in very-long-baseline interferometer (VLBI) observations of black holes. En route to demonstrating the likely very small differences between these theories, we develop a completely theory-agnostic approach which is sufficiently general to be used for other similar studies."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Studies of quadratic gravity with chaos and instability"]}]}],"canonical_facts":{"dc:contributor":["Yunes, Nicolás","Gammie, Charles","Noronha-Hostler, Jacquelyn","Filippini, Jeffrey"],"dc:creator":["Deich, Alexander"],"dc:date":["2024-12-05","2024-12"],"dc:description":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms","The student, Alexander Deich, accepted the attached license on 2024-12-02 at 20:39.","The student, Alexander Deich, submitted this Dissertation for approval on 2024-12-02 at 20:46.","This Dissertation was approved for publication on 2024-12-05 at 11:37.","DSpace SAF Submission Ingestion Package generated from Vireo submission #21460 on 2025-03-28 at 14:27:53","From gravitational wave detectors to very long baseline interferometers, experimental relativity is being born. With the promise of troves of data from the space very near black holes, we are at the cusp of having a sharper view of the most extreme gravitational environments than ever before. In addition, the last half- century of theoretical work has provided a trove of potential modifications to the theory of gravity which we might test with the incoming new data. One approach to testing these theories is to look at what the trajectories of test particles can tell us about the underlying theory, and how we might be able to make observations of those particles with current and future instruments. In particular, the extent to which these trajectories exhibit signs of instability and chaos offer a unique, and in principle independent, test of the metrics which govern their motion. In this dissertation, we focus on how we might test two theories of gravity, dynamical-Chern-Simons (dCS), and scalar-Gauss-Bonnet (sGB). We begin with testing to what extent dynamical chaos may present itself in massive test particle trajectories around black holes in these theories. We show that while these theories may permit chaotic orbits, any features are likely too tiny to be detectable in extreme-mass-ratio inspiral (EMRI) signals in near-future detectors. Then, we look at how the spin expansion order of the metrics may impact the precision of calculated observables. We show that for all but the most rapidly spinning black holes, many astrophysical observables may be calculated with only the first half dozen expansion terms. Finally, we investigate how the instability of photon trajectories in black hole solutions may lead to differences in very-long-baseline interferometer (VLBI) observations of black holes. En route to demonstrating the likely very small differences between these theories, we develop a completely theory-agnostic approach which is sufficiently general to be used for other similar studies."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/127257"],"dc:language":["en","eng"],"dc:rights":["Copyright 2024 Alexander Deich"],"dc:subject":["Gravity","Black Holes","Chaos","Vlbi","Ligo","Lisa","Lyapunov","Poincare"],"dc:title":["Studies of quadratic gravity with chaos and instability"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:03Z"}