Events List

DateEvent TypeSpeaker
04/02/2024Astro SeminarThales Gutcke [ + ]
04/02/2024Grad Pheno Journal Club [ + ]
04/03/2024ArXiv DiscussionHEP/Pheno Journal Club [ + ]
04/03/2024HEP SeminarTaewook Youn [ + ]
04/04/2024Physics Dept ColloquiumItai Cohen [ + ]
04/05/2024HEP Discussion SessionsZare [ + ]
04/09/2024Astro SeminarMatthew McQuinn [ + ]
04/10/2024Special SeminarOr Graur [ + ]
04/10/2024HEP SeminarClifford Cheung [ + ]
04/11/2024Physics Dept ColloquiumKaren Kasza [ + ]
04/12/2024HEP Discussion SessionsZare [ + ]
04/16/2024Grad Pheno Journal Club [ + ]
04/17/2024ArXiv DiscussionHEP/Pheno Journal Club [ + ]
04/17/2024HEP SeminarDeog Ki Hong [ + ]
04/17/2024Cosmic Happy HourTony Zhou [ + ]
04/18/2024Informal HEP TalkThomas Faulkner [ + ]
04/18/2024Physics Dept ColloquiumJohn Eiler [ + ]
04/19/2024Informal HEP TalkEdward Mazenc [ + ]
04/19/2024Special SeminarJohn Eiler [ + ]
04/19/2024HEP Discussion SessionsZare [ + ]
04/22/2024CCPP Brown BagDavid Hogg [ + ]
04/23/2024Astro SeminarNikhil Padmanabhan [ + ]
04/23/2024Grad Pheno Journal Club [ + ]
04/24/2024HEP SeminarT Daniel Brennan [ + ]
04/25/2024Oral DefenseNicholas Faucher [ + ]
04/25/2024Physics Dept ColloquiumDavid Awschalom [ + ]
04/26/2024HEP Discussion SessionsZare [ + ]
04/29/2024CCPP Brown BagGiovanni Verza [ + ]
04/29/2024Informal HEP TalkTrakshu Sharma [ + ]
04/30/2024Astro SeminarAnna Suliga [ + ]
04/30/2024Grad Pheno Journal Club [ + ]
05/01/2024ArXiv DiscussionHEP/Pheno Journal Club [ + ]
05/01/2024HEP SeminarMichael Toomey [ -- ]

Title: Cosmic Tensions and Early Dark Energy
Abstract: Cosmological datasets consistently exhibit growing tension with the Λ Cold Dark Matter (ΛCDM) model of cosmology. The most striking discrepancy is between direct measurements of today's expansion rate (H0) using Cepheid-calibrated supernovae and the expansion rate inferred from ΛCDM fits to early-Universe data sets, namely the cosmic microwave background (CMB). This discrepancy now sits at a 5σ tension. More recently, measurements of galaxy clustering, as parameterized by the amplitude of dark matter density fluctuations (σ8), suggest further tension within the concordance model. One leading proposal to resolve the H0 tension is Early Dark Energy (EDE), which posits a slow-rolling scalar field active shortly before CMB formation. This field acts as a new, brief source of energy injection, modifying the size of the sound horizon—a critical standard ruler for constraining H0. In the first half of this talk, I will discuss the most recent constraints from combined analyses of CMB and large-scale structure datasets, which show that the original axion-like EDE model is strongly disfavored. I will also demonstrate that these constraints are not influenced by prior volume effects, which have been argued to artificially disfavor the model in Bayesian MCMC analyses of EDE. In the final part of the talk, I will present the first constraints on early dark energy using theory-informed priors in an analysis with CMB and large-scale structure datasets. Leveraging normalizing flows, a type of machine learning architecture, this represents the most stringent constraints on the model to date. Along the way, I will also comment on some general insights gained from the detailed analysis of the EDE scenario and how this should inspire model builders to construct future, well-motivated extensions of ΛCDM. (2:00 PM - 3:00 PM, 726 Broadway, 940, CCPP Seminar)
05/02/2024Oral DefenseXucheng Gan [ + ]
05/02/2024Oral DefenseConghuan Luo [ + ]
05/02/2024Physics Dept ColloquiumKathleen Stebe [ + ]
05/03/2024HEP Discussion SessionsZare [ + ]
05/03/2024Oral DefenseMilad Noorikuhani [ + ]
05/06/2024CCPP Brown BagPatrick Breysse [ + ]
05/07/2024Grad Pheno Journal Club [ + ]
05/10/2024HEP Discussion SessionsZare [ + ]