Chemistry 108

Titin-based Molecular Underpinnings of Skeletal and Cardiac Muscle Function
Jorge Alegre-Cebollada, PhD
Associate Professor & Group Leader, CNIC (Spanish National Center for Cardiovascular Research)

Titin is the largest protein in the human body. The function of the protein is not any smaller: it is critical for the contractile activity of muscles in the skeletal system and in the heart. In my presentation, I will introduce fundamental concepts that link titin nanomechanics with the macroscopic mechanical function of muscle. I will focus on our recent data demonstrating dysregulation of titin nanomechanics that can contribute to increased risk of heart failure in diabetic patients.

Superconductors Investigated by High-Energy Particle Irradiation
Dr. Kyuil Cho, Assistant Professor
Department of Physics, Hope College

Superconductor is a material that shows zero resistivity and Meissner effect below its critical temperature. This material has been used for various applications such as superconducting wires, medical device MRI, superconducting magnets for particle accelerators, quantum computing circuits, and many more. The superconductivity research group at Hope College conducts unique research on novel superconductors by using high energy particles. High energy particle irradiation is a useful method to generate homogeneous artificial defects on superconductors. By investigating how the defects affect the properties of superconductors, one can uncover the fundamental mechanism of superconductivity.

This week's Physics Colloquium has been cancelled.

Gravitational Waves from Galactic Nuclei
Nicholas Stone, Assistant Professor
Department of Astronomy, University of Wisconsin-Madison

The discovery of GW150914 inaugurated the era of gravitational wave (GW) astronomy, opening a new window to study our Universe's compact objects and through which to test general relativity. Now, a decade later, the LIGO-Virgo-KAGRA (LVK) collaboration has seen hundreds of GW signals, overwhelmingly from mergers of binary stellar mass black holes. Despite the many successes of GW astronomy, a zeroth-order astrophysical question remains unanswered: what astrophysical environments produce the LVK binary black holes, and by what process are they assembled? Although many formation channels have been proposed, one uniquely testable solution is the "AGN channel:" a scenario in which individual black holes pair up and merge in the dissipative gaseous environment of an active galactic nucleus.

Constraining Common Envelope Evolution Simulations with Observations
Sarah Villanova Borges, PhD Candidate
University of Wisconsin-Milwaukee

Common Envelope Evolution (CEE) remains one of the biggest unresolved problems in binary stellar evolution, despite being the primary pathway for the formation of close binary systems. One of the main challenges in understanding CEE is its intrinsically multiscale and multiphysics nature, which makes it difficult to model with analytical or 1D models. 3D hydrodynamical simulations have therefore become essential tools for studying this phase. However, validating these simulations requires observational constraints, which are scarce. This lack of direct observations is another major obstacle in modeling CEE. One exception is luminous red novae, which is believed to correspond to CEE events that culminate in stellar mergers.

Studying Magnetism with Resonant X-ray Scattering at Advanced Photon Source
Jong-Woo Kim, Physicists
Magnetic Material Group/Advanced Photon Source, Argonne National Laboratory

X-ray scattering at synchrotron facilities such as the Advanced Photon Source provides a powerful platform for investigating magnetic order with element and orbital specificity. In this colloquium, I will introduce the fundamentals of single-crystal X-ray diffraction and the principles of resonant elastic X-ray scattering (REXS), emphasizing how tuning to absorption edges enhances sensitivity to electronic and magnetic structures.

Combining Quantum Master Equations with Linearized Semiclassical Methods to Simulate Electronic Energy & Charge Transfer Dynamics in Complex Molecular Systems
Professor Eitan Geva, Department of Chemistry
University of Michigan - Ann Arbor

Photo-induced electronic energy and charge transfer plays a key role in a variety of chemical, biological and technologically-important molecular systems. The simulation of the
underlying electronic dynamics is challenging due to its intrinsically quantum mechanical nature and the large number of coupled electronic and nuclear degrees of freedom involved. Quantum master equations provide a flexible and general-purpose framework for addressing this challenge.

Physics Colloquium - Ronan Humphrey, UWM Physics
Presentation title and abstract will be announced when they are available.

Physics Colloquium - Lulu Agazie, UWM Physics Presentation title and abstract will be announced when they are available.

What Are We Learning About Super-Eddington Accretion Disks From Simulations?
Professor Chris Fragile
Department of Physics & Astronomy, College of Charleston

Accretion of gas onto black holes is one of the most important processes shaping our Universe. Understanding extremely high rates of accretion (dubbed 'super-Eddington') is vital to explaining the challenging observation that supermassive black holes (SMBHs) are fully formed at redshifts >7. It is also important to understanding astrophysical objects such as tidal disruption events (TDEs) and ultra-luminous X-ray sources (ULXs).