2026-09-18T23:01:11Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/132475 2026-02-20 col_2142_5131 col_2142_8859 com_2142_5130 com_2142_8858 com_2142_234

application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms The student, Nicki Mullins, accepted the attached license on 2025-10-28 at 09:04. The student, Nicki Mullins, submitted this Dissertation for approval on 2025-10-28 at 09:12. This Dissertation was approved for publication on 2025-10-28 at 12:55. DSpace SAF Submission Ingestion Package generated from Vireo submission #22837 on 2026-02-19 at 18:24:27 Causal and stable stochastic relativistic hydrodynamics Mullins, Nicki 2025-10-28 Noronha, Jorge Noronha-Hostler, Jacquelyn Sickles, Anne Witek, Helvi stochastic dynamics relativistic hydrodynamics quark-gluon plasma heavy-ion collisions high-energy nuclear theory eng Heavy-ion collisions lead to the creation of one of the most exotic known types of fluids, the quark-gluon plasma. Due to the small size of the created system and the expected presence of a critical point in the transition from ordinary hadronic matter to the quark-gluon plasma, thermal fluctuations should be important in the modeling of this matter. In this dissertation, we focus on causal and stable formulations of stochastic relativistic hydrodynamics. Connections between causality, stability, and the foliation independence of equal-time fluctuations are used to formulate stochastic hydrodynamics in the linear regime. This approach is applied to several conventional theories of relativistic hydrodynamics, finding that new subtleties appear when fluctuations are included. To extend these results to the nonlinear regime, we consider effective action approaches. The standard procedures can lead to a non-convergent path integral and non-positive definite noise, so we introduce a new effective theory based on Crooks fluctuation theorem. This effective theory is applied to divergence-type hydrodynamics, in which case the path integral can converge and both causality and stability conditions can be enforced with relative ease. This formulation leads to equations that are flux conservative and so can be simulated using the Metropolis algorithm, supporting the inclusion of stochastic fluctuations in the modeling of heavy-ion collisions. 2025-12 Thesis https://hdl.handle.net/2142/132475 Copyright 2025 Nicki Mullins Physics Physics University of Illinois Urbana-Champaign Ph.D. Dissertation