Upcoming Events For Colloquia

IceCube: Opening a New Window on the Universe from the South Pole

Prof. Francis Halzen
Wisconsin IceCube Particle Astrophysics Center and Department of Physics
University of Wisconsin–Madison

We will review the scientific motivation and the early R&D that eventually led the IceCube project to transform a cubic kilometer of natural Antarctic ice into a neutrino detector. The instrument detects more than 100,000 neutrinos per year in the GeV to 10 PeV energy range. Among those, we have isolated a flux of high-energy neutrinos of cosmic origin, with an energy density similar to that of high-energy photons and cosmic rays in the extreme universe. We identified their first source: on September 22, 2017, several astronomical telescopes pinpointed a flaring galaxy, powered by an active supermassive black hole, as the source of a cosmic neutrino with an energy of 290 TeV. Archival IceCube data subsequently revealed a flare in 2014-15 of more than a dozen neutrinos from the same direction. Accumulating evidence suggests that the first cosmic ray accelerator belongs to a special class of active galactic nuclei that is responsible for the origin of the highest energy particles in the Universe.…

Lab TA Feedback with [Re]Active Negative Tone Tolerated by Students with [Pro]Active Learning Overall

Prof. Abigail Mechtenberg
University of Notre Dame

At a rate between 700-900+ students/year implementation of this novel experimental design (ED) pedagogy, 5 years of data have been collected. This ED pedagogy moves an Active Physics lab culture from cookbook labs into inquiry-based labs, and towards a final project with the overarching goal of connecting to research or student driven interests. Building upon pattern recognition within cookbook labs and anthropological norms of doing science, ED-labs focus on three thought spheres: measurements (M), calculations (C), and variations (V). In addition to spheres of thinking, ED-labs connect these thought spheres to develop analysis pathways of processing science (MCV/VCM/CMV/MVC/VMC/CVM): derivation versus regression-based analysis pathways each with distinct error and/or uncertainty conclusions. Finally, all ED-labs/projects move through the thought spheres and processing pathways in four lab stages: Design, Data, Analysis, and Communication. With Google Classroom, students submitted their AIP formatted lab reports. Subsequently, lab TAs wrote lab report feedback comments, as well as returned these comments with rubric-based lab report grades. For 797 lab reports in Spring 2018, all 8,731 Lab TA comments were analyzed in terms of total words, tone, complexity, probing level, and balance between judging and advising categories. The hypothesis was that the tone of Lab TA comments were correlated to student lab course evaluations and final exam scores. Tone and probative comments correlated and were able to predict student lab course evaluations, yielding an understanding that negative tone comments can be tolerated by students if the comments strongly probe the students. However, probative comments, and a balance between judging and advising comment categories were correlated. Together, they were able to predict the student lab final exam score. Fascinatingly, tone was not at all correlated to the lab final exam score. We discuss future research into the potential Active Physics classroom culture differences in terms of [Re]Active and [Pro]Active cultural roles in which teachers and students inhabit, thereby influencing their relationships to hinder/enhance knowledge development and scientific creativity. The [Re]Active Teaching/Learning pair is discussed as Judge-Teaching Assistant (J-TA) paired with Cookbook-Lab Learner (CL-L), and the [Pro]Active Teaching/Learning pair is discussed as Adviser-Teaching Assistant (A-TA) with Inquiry-Lab Learner (IL-L). …

Blurry old pictures: Noise, memory, and the challenge of the quantum many-body problem

Prof. Joaquin Drut
Department of Physics and Astronomy
The University of North Carolina at Chapel Hill

Quantum many-particle physics, broadly defined to include areas from condensed matter to QCD, can be viewed as a rich Venn diagram displaying multiple intersections. The connections arise from shared physical insight (e.g., universality in phase transitions) as well as from shared methodological approaches (e.g., Feynman diagrams). Unfortunately, these areas also share the same practical misfortunes: deep computational problems coming directly from the Schroedinger equation, which reappear in a different form in Feynman’s path-integral formalism. In this talk, I will walk you through the origin and nature of these issues, explain why they stand in the way of progress across multiple fields in physics, and outline a taxonomy of ideas to overcome them. I will then present a new and very different kind of approach to tackle the finite-temperature thermodynamics of nonrelativistic quantum systems (e.g., neutron matter and ultracold atoms). Finally, I will show you a few selected results obtained with that method which go well beyond what was thought possible only a few years ago.…

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Prof. Anna Simon
Department of Physics, University of Notre Dame…

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Prof. Alex Lazarian
Department of Astronomy
University of Wisconsin-Madison…

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Prof. Robert V.F. Janssens
University of North Carolina

Hosted by Prof. Brodeur

All interested persons are invited to attend remotely—email physics@nd.edu for information.…

Progress of the KAGRA Gravitational Wave Collaboration

Prof. Quynh Lan Nguyen
Department of Physics
University of Notre Dame…