Physics Colloquia

Professor Scott A. Hughes, Dept. of Physics & the Kavli Institute, MIT

High-precision Waveforms with the Small-mass-ratio Limit

Current gravitational-wave detectors are being upgraded, and plans are developing for future detectors with greater sensitivity over broader frequency bands. As instruments improve and develop, more cycles of sources’ gravitational waveforms will be measured with greater signal to noise ratio. Such higher fidelity measurements promise to teach us more about their sources and the nature of strong-field gravity — but only if theoretical modeling of these waves is able to match advances in the detectors. As we measure waveforms with better precision, the likelihood increases that systematic modeling errors will affect inferences about what we measure.

In this talk, I will survey recent progress modeling waveforms from small-mass binaries. Such binaries, which exactly describe important low-frequency gravitational wave sources, also serve as a limit of the more general binary problem that can be modeled with very high precision. I will discuss the outstanding progress that has been made on this problem in recent years, and how what we learn in this limit can be combined with other binary modeling techniques to advance modeling for relativistic binaries in general.

Scott Hertel, Assoc. Professor, Dept. of Physics, University of Massachusetts-Amherst

Recent Progress Towards the Detection of Dark Matter

As you read this, you are immersed in a bath of particles beyond the Standard Model, so-called ‘dark matter’ particles which are noticed only through their gravitational effects at astrophysical scales. Discovering the properties of these unseen particles (their mass, interactions with other particles, etc.) is one of the great challenges of 21st century physics.

I will describe two complementary efforts which search for individual dark matter particles in a laboratory setting here on earth: LZ and TESSERACT. Each effort search Centeres for the individual scatters of galactic dark matter particles with atoms here on earth, and each effort requires the development of novel and interesting technologies. I will update you on our progress towards unraveling this great mystery of physics.

Geoffrey Bower, Chief Scientist for Hawaii Operations, Academia Sinica Institute of Astronomy and Astrophysics

Imaging Black Holes with the Event Horizon Telescope

The Event Horizon Telescope (EHT) is a global submillimeter-wavelength very long baseline array that produces the highest angular resolution images of black holes. The EHT Collaboration has produced images of two black holes, the supermassive black hole in the elliptical galaxy M87 and the Galactic Center black hole, Sgr A*.

In this talk, I will describe the techniques and technology behind these measurements, give updates on the latest results, and plans for future observations. Images of both sources have a ring-like morphology consistent with predictions of general relativity and the Kerr metric.

The event flyer is available here.

David Hogg, Professor of Physics & Data Science, NYU

Sailing as Momentum Transport

Sailboats represent an ancient (but newly relevant) sustainable form of transportation. They work off the relative velocity between the air and the water. Sailboats can sail upwind (by tacking), they can sail downwind faster than the wind (also by tacking), and they can sail crosswind much faster than the wind.

I present the simplest possible momentum transport model of a sailboat, and explain all of these capabilities. In this (spherical scow) model, the sailboat is defined by three dimensionless numbers: the sail-to-keel area ratio, a lift ratio for the sail, and a lift ratio for the keel. The model makes a number of amusing "predictions" that explain the properties of commercial and competitive sailboats. There are many connections to sustainable energy.

The event flyer is available here.

UWM Physics Post docs, graduate student, and faculty

Spring 2025 APS Preview Talks

Members of the UWM Physics department will present their preview talks in preparation for the upcoming APS meetings

The event flyer is available here.

Shashwat Sardesai, PhD Candidate, UWM Physics

Cosmic Orchestra: The Gravitational Wave Background

In the last year and a half, the North American Nanohertz Observatory for Gravitational Waves, and their collaborators, have detected the presence of a gravitational wave background using pulsar timing arrays. These gravitational waves likely arise from supermassive black hole binaries (SMBHBs) and have periods spanning years or decades.

In this talk, I will go over the basics of PTAs, the different methods to analyze the background, as well as the projects I have worked on as a member of the NANOGrav collaboration to try and resolve aspects of the GWB.

The event flyer is available here.

Sheng Ran, Assistant Professor of Physics, Washington University

Strongly Correlation and Topology in Kondo Lattice Systems

Quantum materials with both strong correlations and nontrivial band structure topology can have novel physics properties that do not exist in the non-correlated counterparts. Recent theoretical work has demonstrated that combination of Kondo physics and nonsymmorphic crystal symmetries can give rise to such strong correlated topological systems.

In this talk, I will present our recent experimental exploration this direction. In one case, we found intrinsic anomalous Hall effect that seems to break the Fermi liquid scaling relation. In another case, we have discovered a candidate for topological Kondo insulator.

The event flyer is available here.

Speaker: Gabriel Freedman, PhD Candidate – UWM Physics Low-frequency Gravitational Wave Searches and Data Analysis with Hamiltonian Sampling The pulsar timing array community has found evidence for a correlated stochastic signal following the Hellings-Downs pattern indicative of an isotropic stochastic …

Speaker: Ned Budisa, Professor & Research Chair, Dept. of Chemistry, University of Manitoba Expanding the Genetic Code via Directed Evolution: Tools for Biophysicists, Materials Science, and Beyond Reprogramming the genetic code to include non-canonical amino acids (ncAAs) is a powerful …

Speaker: Dr. Katey Alatalo, Assistant Astronomer, Space Telescope Science Institute The Life-cycle of Gas in Dying Galaxies Modern day galaxies populate a bimodal distribution, in both morphology and color space. Their morphological and color properties are also inter-related, with lenticular …