Events at Physics |
Events on Wednesday, April 12th, 2023
- GREAT IDEAS DEI Reading Group
- GREAT IDEAS Coffee Hour
- Time: 12:15 pm - 1:15 pm
- Abstract: GREAT IDEAS Cancelled for this week - see you April 26th!
- Host: GMaWiP and Climate and Diversity Committee (contact Jessie Thwaites or R. Sassella with questions)
- Department Meeting
- Closed Department Meeting
- Time: 12:15 pm - 1:30 pm
- Place: VIRTUAL - link will be sent later.
- Speaker: Mark Eriksson, UW-Madison
- Closed meeting to discuss personnel matters—pursuant to Section 19.85(1)(c) of the Wisconsin Open Meetings Law Closed to all but tenured faculty
- Host: Mark Eriksson
- Theory Seminar (High Energy/Cosmology)
- Late-time accelerating cosmologies
- Time: 1:00 pm - 2:30 pm
- Place: Chamberlin 5280
- Speaker: Flavio Tonioni, UW Madison
- Abstract: In this talk, I will characterize the late-time expansion rate of the universe in scalar-field cosmologies with multi-exponential potentials. To do this, I will take advantage of previously unobserved universal asymptotic features of the solutions to the cosmological equations. This is a critical achievement because it provides a simple diagnostic of whether any given multi-exponential potential holds the necessary conditions for late-time cosmic acceleration. Such potentials have been studied extensively as phenomenological models of quintessence and, moreover, they are ubiquitous in string-theoretic constructions, which further allows one to sharpen several statements on the low-energy signatures of quantum gravity. I will extensively comment on the tension for acceleration posed by the string-theoretic dilaton, which, if present as a rolling scalar in a weakly-coupled theory, makes the potential too steep for acceleration unless negative-definite potentials are present. I will also show that, if the late-time scale factor is of power-law form, the acceleration parameter can be expressed in terms of a directional derivative of the potential.
- Host: George Wojcik
- The James Webb Space Telescope - Launching a New Astronomical Era
- Time: 6:00 pm - 7:00 pm
- Place: Chamberlin 2241
- Speaker: Dr. Steph LaMassa, Space Telescope Science Institute
- Abstract: The James Webb Space Telescope revolutionized astronomy with its launch in 2021 and first science images in 2022. Already, it has revealed some of the farthest galaxies ever discovered, analyzed the atmospheres of planets orbiting distant suns, and studied some of the largest stars in the universe. Dr. Stephanie LaMassa, branch manager for the Near-Infrared Imager and Slitless Spectrograph (NIRISS) aboard JWST, will teach about the design, launch, and software maintenance of JWST and NIRISS. Being in charge of the instrument, Dr. LaMassa will provide unique insight into how instruments intended for spaceflight are designed, and how students can get involved with instrumentation work on the ground. In addition, she will also talk about some of the exciting uses for the space telescope, including studies of supermassive black holes and the earliest galaxies in the universe.
- Host: Astronomy Club at UW - Madison