Unless otherwise noted, all colloquia will be held from 3-4 pm in the Biosciences Building (BSB), room 3.03.02.
Spring 2026 Schedule
| Colloquium Date | Colloquium Presenter |
|---|---|
| February 2, 2026 | Generative Artificial Intelligence Methods for Plasma Physics Computations Dr. Diego Del Castillo Negrete February 2 abstract We report recent progress on generative artificial intelligence (AI) methods to accelerate turbulence simulation and kinetic computations of plasmas of interest to controlled nuclear fusion. These plasmas are far-from-equilibrium, strongly nonlinear systems exhibiting complex spatiotemporal multiscale dynamics that result in formidable computational challenges. For turbulence, we present the GAIT (Generative Artificial Intelligence Turbulence) framework based on the coupling of convolutional variational autoencoders, that encode precomputed turbulence data into a reduced latent space, and recurrent neural networks and decoders that generate new turbulence states [1]. Applications to plasma turbulence fluid models, exhibiting 400X acceleration, and gyrokinetic models are presented. For kinetic problems, we report progress on the use of AI methods to accelerate particle-based computations. These computations are time-consuming due to the need to follow large ensembles of particles to avoid statistical sampling errors. The physics models of interest are Fokker-Planck equations for the particle distribution function in phase space. The AI methods include Normalizing Flows and Diffusion Models [2]. Convergence analysis, along with numerical test experiments are provided to demonstrate the effectiveness of the proposed methods. Applications include transport in 3D chaotic flows, and runaway electrons in magnetically confined fusion plasmas. [1] B. Clavier, D. Zarzoso, D. del-Castillo-Negrete and E. Frenod, Phys. Rev. E Letters 111, L013202 (2025); Physics of Plasmas 32 063905 (2025). |
| February 9, 2026 | Mathematical Modeling of Within-Host Dynamics of Mycobacterium Tuberculosis Dr. Vitaly Ganusov February 9 abstract Mycobacterium tuberculosis (Mtb) are bacteria causing disease tuberculosis (TB). Mtb has been with humans for thousands of years. Some estimates suggested that over 1 billion people died from TB over the course of human history. Bacillus Calmette-Guérin (BCG) is a vaccine that was developed in the early 20th century as a means to prevent TB in children, and since its widespread use over 4 billion individuals have been vaccinated with BCG. We know that BCG is highly protective in children against TB but how it provides protection remains incompletely understood. In my talk I will discuss our mathematical modeling-based analyses of experimental data on Mtb dynamics in mice immunized with BCG. I will highlight how mathematics is useful at interpreting experimental data, at making predictions, and at suggesting experiments that are most informative. I will present a concept of strong inference in mathematical modeling that emphasizes the best practices of applying mathematics in life sciences. |
| February 23, 2026 | A New Waring's Problem for Quadratic and Hermitian Lattices Dr. Jingbo Liu February 23 abstract For each positive integer n, let gz(n) denote the smallest positive integer with the following property: whenever a positive definite integral quadratic form in n variables can be expressed as a sum of squares of integral linear forms, it can in fact be expressed as a sum of gz(n) such squares. In this talk, we prove that as n → ∞, the growth of gz(n) is at most an exponential of √n. We also introduce an analogous invariant gd(n) for Hermitian lattices over the ring of integers in an imaginary quadratic field E=Q(√-d), and we give an algorithm that determines the explicit value of gd(1). Finally, we discuss potential applications of this new Waring's problem to lattice-based cryptography. |
| March 16, 2026 | Magic Hamiltonian Dr. Marius Junge March 16 abstract I had to learn from experimentalists in quantum information theory that there are magic gates, which are harder to implement but can boost a cheap set of gates to a set of gates allowing to perform arbitrary quantum computation. In this talk, the magic Hamiltonian will be discussed, an analogue of magic gates in the realm of Lie algebras. Indeed, the famous Ising-Hamiltonian with magnetic field terms serves as a boost to exponentially increase the dimension of the generated Lie algebra. The aim of this talk is to illuminate the simple mathematical background, discoveries, and challenges in finding magic self-adjoint matrices which serve to improve quantum computation. This is joint work with Luke Visser and Jason Polack. |
| March 23, 2026 | LLM-Enhanced Learning: A Thought-Partner Alternative Dr. Tony Thrall March 23 abstract The emergence of LLM-based learning tools presents both opportunities and risks for data science education. Most current tools default to answer-provision, which risks undermining the deep understanding that employers increasingly demand. This presentation surveys the landscape, diagnoses the structural incentives behind the answer-provider problem, and proposes a "thought-partner" alternative grounded in five pedagogical principles. An instantiation of this approach—the EDA Companion—is currently in alpha testing. |
| March 30, 2026 | Leveraging Student Thinking: Taking Active Learning to the Next Level Dr. Jessica Gehrtz March 30 abstract At the K-12 level, there is evidence that instruction that leverages student thinking can lead to increased conceptual understanding and success for students. The ways in which instructors leverage student thinking in undergraduate STEM contexts, and what enables them to do so effectively, remains largely unexplored. We investigated how undergraduate STEM faculty use student thinking in their teaching, focusing on faculty who engage students in active learning during class. From analyzing interviews and video of a class lesson for eight undergraduate STEM instructors, we identified a group of instructors who exhibited high levels of leveraging student thinking and a group of instructors who exhibited low levels of leveraging student thinking. In this talk, I will discuss key similarities and differences between these two groups of instructors and possible explanations for why some STEM instructors are leveraging student thinking and others are not. |
| April 6, 2026 | Transmission Dynamics of Eastern Equine Encephalitis: Global Sensitivity Analysis and SHAP Parameter Importance in an Age-Structured Vector-Host Model Dr. Christopher Mitchell April 6 abstract Abstract: Eastern equine encephalitis virus (EEEV) is a deadly arboviral pathogen with 30% severe case fatality. EEEV exhibits pronounced 2–3 year cyclical outbreak patterns in the northeastern United States, linked to shifts in mosquito feeding preferences between hatch year and adult avians. We developed an age-structured vector-host model incorporating differential feeding patterns of Culiseta melanura mosquitoes on European Starlings and American Robins. Global sensitivity analysis revealed mosquito biting rate (α) as the dominant driver in transmission, with avian infectivity (δ) and exposure (α) playing secondary roles. Pairing tree-based machine learning algorithms with SHAP analysis on 100,000 parameter sets identified parameter hierarchies that govern cyclic transmission. Adult avian mortality (μα) was identified as the key parameter underlying cyclic and stable transmission patterns. SHAP further revealed these patterns to be grounded on opposite sides of the same epidemiological mechanism. Stable endemics emerge from demographic stability paired with transmission optimization, while cyclic endemics emerge from demographic instability paired with minimal transmission optimization. Numerical simulations illustrated critical threshold dynamics at 0.2 ≤ α ≤ 0.4, where heightened hatch-year exposure triggers demographic instability responsible for observed 2–3 year cycles, while balanced exposure (α ≈ 0.5) leads to stable endemics. These mechanisms provide a foundation for targeted surveillance and control interventions. |
| April 13, 2026 | Catalyzing Productive Conversations About Teaching—For K–12 Teachers and College Math Instructors Dr. Cody Patterson April 13 abstract This talk is a tale of two projects, both aimed at a common set of guiding questions: what can we do to support teachers in having more productive conversations about mathematics teaching, and how do we know when we are succeeding? I will start by sharing results from a study of teachers working together in an informal summer mathematics program for children ages 10-14. Each day these teachers collaboratively taught a class for four hours in the morning, then met in the afternoon to reflect on the student thinking they had witnessed, examine the practice of responding to this thinking, and make plans for future classes. Our research team analyzed the intellectual resources the teachers (both preservice and in-service) contributed to these conversations, and how the interplay among these resources enriched opportunities for teacher learning. In the second half, I will share some efforts—some of my own, and some from my work with the CoMInDS community—to enrich the conversations that graduate teaching assistants have about teaching in professional development seminars and workshops. I will share some tools that I have designed for TA professional development and some initial evidence of the opportunities they may provide for TA learning. In both parts of the talk, I will share what I have learned about the role of representations and approximations of practice in setting the stage for productive conversations about teaching. |
| April 20, 2026 | Moving Forward: Fostering Quantitative Reasoning in its Absence Dr. Kevin Moore April 20 abstract A growing body of evidence suggests that students' quantitative reasoning is critical for their success in STEM courses and fields. Quantitative reasoning supports their problem-solving abilities, their modeling processes, and their ability to use STEM ideas in everyday life. Despite its importance, common curricular approaches—particularly in mathematics—largely lack an intentional focus on quantitative reasoning. Complicating matters further, common curricular approaches to several key mathematical ideas stand in opposition to quantitative reasoning approaches. Supporting students' quantitative reasoning thus requires giving attention to both the extant meanings students bring to the classroom and the quantitative reasoning-based meanings one intends for them to learn. In this talk, I identify one approach to addressing this issue. I also use this approach to discuss broader issues of supporting students' quantitative reasoning, including the importance of students' quantitative reasoning for creating productive mathematics education research settings. |
| May 1, 2026 | Nonnegativity Certificates and Polynomial Optimization Dr. David Papp May 1 abstract At its simplest, "polynomial optimization" refers to nonlinear optimization problems in which the goal is to find the (global) optimal value of a polynomial over a set defined by polynomial inequalities. It is an NP-hard class of computational problems (even when all polynomials involved are quadratic) but has attracted significant interest because of its many applications both within and well outside the mathematical sciences. In a broader sense, "polynomial optimization" also refers to optimization problems with constraints that a polynomial (whose coefficients are to be determined) must be nonnegative over some domain. These constraints are convex, yet intractable—at the heart of all these problems is the deceptively simple question: how can we tell if a polynomial is nonnegative (on a given domain)? After some motivating applications, we will give a brief introduction to the fundamental theoretical results and algorithmic tools in the area: nonnegativity certificates (such as sum-of-squares approximations) and their connection to linear, semidefinite, and non-symmetric conic optimization. The talk will be self-contained and will not assume any familiarity with optimization beyond standard Calculus material. Location: FLN 2.02.02 |
