Physics & Astronomy

Physics Colloquium - Jorge Alegre-Cebollada
2026-05-22 15:30 - 17:00 (America/Chicago) | Chemistry 108, 2050 E Kenwood Blvd, Milwaukee, WI, 53201, United States
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.
Towards the end of my presentation, I will describe how to harness titin mechanics to develop hydrogels with tailored viscoelasticity for applications in cell mechanobiology. Time permitting, I will discuss about new models to study titin mechanics in living matter.

Physics Colloquium - Kyuil Cho
2026-05-08 15:30 - 17:00
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.
In this talk, recent investigations on YBCO (0.6 and 1.7 MeV proton) and NbSe2 (2.5 MeV electron) will be presented.

Physics Colloquium - Cancelled
2026-05-01 15:30 - 17:00
This week’s Physics Colloquium has been cancelled.

Physics Colloquium - Nicholas Stone
2026-04-17 15:30 - 17:00
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. I will review recent progress in understanding the ecology of stars and black holes embedded in the massive gas disks of AGN, an astrophysics problem not unlike that describing planet formation in protoplanetary gas disks. I will then describe the unique predictions of the AGN channel for the LVK population of binary black hole mergers, focusing both on GW signatures as well as electromagnetic counterparts, both direct (transient) and indirect (statistical). Finally, I will briefly discuss the implications of the AGN channel for a future class of GW sources: the extreme mass ratio inspirals visible to future mHz space-based interferometers such as LISA, which are produced when stellar mass black holes inspiral into the supermassive ones at the very centers of active or quiescent galactic nuclei.

Physics Colloquium - Sarah Villanova Borges
2026-04-10 15:30 - 17:00
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. In contrast, there are no confirmed direct detections of ongoing CEE events that result in the survival of a close binary. As a result, studies must rely on observations of post-CEE systems, such as close binaries, planetary nebulae (PNe) and water fountains (WFs), to constrain both numerical simulations and analytical models. Close binaries primarily provide constraints on the final orbital separation between the stellar core and its companion, while PNe and WFs offer insight into the morphology of the ejected envelope.
During my PhD, I focused on constraining CEE hydrodynamical simulations using observations of those post-CEE systems (close binaries, WFs, and PNe). In this colloquium, I will discuss the key insights I have got into the understanding of CEE during my PhD years.

Physics Colloquium - Jong-Woo Kim
2026-04-03 15:30 - 17:00
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.
I will then discuss the microscopic origin of X-ray magnetic scattering and its unique ability to probe spin, orbital, and multipolar order. Finally, selected examples from complex oxides and correlated materials will illustrate how these techniques reveal emergent magnetic phenomena that are difficult to access with conventional probes.

Physics Colloquium - Eitan Geva
2026-03-06 15:30 - 17:00
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.
In this talk, I will overview computational approaches for simulating photo-induced electronic energy and charge transfer dynamics in complex molecular systems that were developed and explored by my group, which combine various types of quantum master equations with linearized semiclassical methods.

Physics Colloquium - Ronan Humphrey
2026-02-27 15:30 - 17:00
Physics Colloquium – Ronan Humphrey, UWM Physics
Presentation title and abstract will be announced when they are available.

Physics Colloquium - Lulu Agazie
2026-02-06 15:30 - 17:00
Physics Colloquium – Lulu Agazie, UWM Physics
Presentation title and abstract will be announced when they are available.

Physics Colloquium - Chris Fragile
2026-01-30 15:30 - 17:00
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).
In this talk, I will present the results of some recent super-Eddington disk simulations and discuss some of the interesting things we are learning.

Physics Colloquium - Moritz Münchmeyer
2025-12-12 15:30 - 17:00
AI Reasoning in Theoretical Physics with the TPBench Project
Assistant Professor Moritz Münchmeyer
UW-Madison Department of Physics
Large-language models are becoming powerful enough to assist physicists with mathematical reasoning at the research level. In this talk, I will first present our dataset TPBench (tpbench.org), which was constructed to benchmark and improve AI models specifically for theoretical physics. I will then discuss how test-time scaling and symbolic verification can be used to improve their performance and reliability.
I will also show preliminary results from two new projects. In the first, we apply reinforcement learning to fine-tune models on QFT problems. In the second, we apply LLM-based code evolution (similar to Google’s AlphaEvolve) to algorithmic problems in cosmology.

Physics Colloquium - Dr. Qiuyan Chen
2025-12-05 15:30 - 17:00
Effect of Phosphorylation Barcodes on Arrestin Binding to a Chemokine Receptor
Dr. Qiuyan Chen
Assistant Professor of Biochemistry & Molecular Biology
Indiana University School of Medicine
Cells often fine-tune their responses to signals through chemical tags called phosphorylation ‘barcodes’ placed on receptors at the cell surface. Different G-protein coupled receptor (GPCR) kinases (GRKs) add these barcodes at different sites, but how these patterns influence arrestins — key proteins that control receptor signaling and trafficking — has been unclear.
In this study, we developed a new molecular tool (Fab7) that helps visualize how arrestin2 and arrestin3 interact with a chemokine receptor called ACKR3 when tagged by either GRK2 or GRK5. We found that GRK2 creates more flexible receptor–arrestin assemblies, whereas GRK5 produces more stable ones. Surprisingly, the arrestins interacted more with the surrounding membrane-like environment than with the usual docking pocket of the receptor, and arrestin3 was more dynamic due to a missing membrane anchoring feature. These findings show that both the “barcode pattern” and the arrestin subtype can shape how GPCRs are regulated, which may help explain differences in cellular outcomes such as how efficiently ACKR3 clears chemokines.

Physics Colloquium - Julian May Mann
2025-11-21 15:30 - 17:00
Physics Colloquium – Julian May Mann, Stanford University
Presentation title and abstract will be announced when they are available.

CANCELLED: Physics Colloquium - Jong-Woo Kim
2025-11-14 15:30 - 17:00
Due to circumstances beyond our control, the Physics Colloquium for Friday, 11/14/2025 has been cancelled.
Jong-Woo Kim, Argonne National Lab

CANCELLED: Physics Colloquium - Justin Goodrich
2025-11-07 15:30 - 17:00
Due to circumstances beyond our control, the Physics Colloquium for Friday, 11/7/2025 is cancelled.
Justin Goodrich, Brookhaven National Laboratory

Physics Colloquium - Pratyusava Baral
2025-10-31 15:30 - 17:00
Detecting & Measuring Gravitational Waves in Current and Future Observatories
Pratyusava Baral
Graduate Student
University of Wisconsin-Milwaukee
Low-latency (near real-time) detection of gravitational waves (GW) is crucial for multimessenger astronomy. I contribute to maintaining and operating the GstLAL-based search pipeline, a flagship detection pipeline used by the LIGO-Virgo-KAGRA collaboration, for the present observing run (May 2023 – ongoing). To test low-latency performance, mock data challenges (MDC) are designed. I studied the latencies of sending out public alerts, used to communicate with astronomers, after a detection using the MDC. I also demonstrated the feasibility of a neural network-based algorithm that identifies the event with the best skymap for multimessenger follow-up from a set of several GW triggers in low latency.
Looking forward to next-generation detectors such as Cosmic Explorer (CE), I developed the first Bayesian framework to estimate errors on inferred parameters, incorporating effects due to Earth’s rotation and the long arm-lengths of the detectors. These effects are important for next-generation detectors and can be used to localize sources on the sky. This framework can analyze long and loud signals in ~1 day and is capable of using waveforms containing higher modes of radiation.

Physics Colloquium - Amanda Baylor
2025-10-24 15:30 - 17:00
Early Warning of Gravitational Waves from Neutron Star Mergers
Amanda Baylor
Graduate Student
University of Wisconsin-Milwaukee
For the past decade, ground-based gravitational-wave observatories have been making detections of ripples in the fabric of spacetime from the mergers of black holes and neutron stars. Mergers involving at least one neutron star could also produce electromagnetic counterparts which may reveal new insights into the physics of these astrophysical phenomena. However, if electromagnetic observatories are not pointed at the location of the source prior to merger, we miss vital information about the physics of merger. This presents a need for early-warning alerts, which are alerts that are sent to observatories once a gravitational wave has been detected but before the objects collide and merge.
This talk will provide an overview of gravitational-wave physics from detection to data analysis and discuss the prospects for early-warning detection of neutron star mergers.

CGCA Public Talk - Searching for Life in the Universe
2025-10-15 18:30 - 20:00
Searching for Life in the Universe
Presented by Dr. Dawn Erb
We hope you will join us on Wednesday, October 15 in the new Chemistry Building, Room #108 for Dr. Dawn Erb’s presentation, “Searching for Life in the Universe.”
This is a free event! Doors open at 6:30 pm with cookies and dessert bars as well as a cash bar. The program will start at 7:00 pm.
Please reserve your free spot for this event. More information is available on the CGCA website.
Due to construction, we recommend you use the parking garage under the Lubar College of Business, located at 3202 N. Maryland Ave. This is a full pay garage that offers ADA parking options near the entrance. You will pull a ticket to enter and pay upon exit. You will find the Chemistry Building by walking south on Maryland to the crosswalk. Head west using the crosswalk on the corner of Maryland Ave. and Kenwood Blvd. The new Chemistry Building is just a half a block, with entrances on Kenwood Blvd. Please be sure to note the restrictions on parking signs if you choose to park on the street.
ADA parking spaces are also available in the front of the Chemistry Building. You will need to pay for parking through the MKE Park Mobile app by using code 59043 which will allow extending the parking session past the 30 minutes limit on the Chemistry circle signs. The hourly rate is $0.80/hour.
Lastly, if you don’t wish to use a parking app, you can call UWM Transportation Services at 414-229-4000 on the day of and pay for parking over the phone. They will collect payment via a credit/debit card. They will ask for your license plate information and email if you would like a receipt. The office is open until 4:30 pm weekdays.
We look forward to seeing you there!

Physics Colloquium - Katey Alatalo
2025-05-09 15:30 - 17:00
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 and elliptical galaxies exhibiting red colors and spiral galaxies usually exhibiting blue colors. In color space, there is a genuine dearth of intermediate colored galaxies, suggesting that the transition a galaxy undergoes to transform must be rapid, and quenching galaxies, rare. Gas – its presence, absence, and mechanics – serves as the anchor of a galaxy’s transformation from blue to red.
I will discuss the nature of gas in transitioning and transitioned galaxies through two lenses: (1) How a galaxy transition is able to impact the behavior of molecular gas, and (2) how new observations of molecular gas in quenching and quenched galaxies has recast our understanding of how they ultimately metamorphose from blue, star-forming spirals into red, quiescent ellipticals and lenticulars.
Location: Chemistry 108
Time: 3:30PM – 5:00PM
Date: May 9th, 2025

Physics Colloquium - Sukanya Chakrabarti
2025-05-02 15:30 - 17:00
Speaker: Sukanya Chakrabarti, Ph. D., Pei-Ling Chan Endowed Chair and Professor, School of Physics and Astronomy, University of Alabama-Huntsville
The Precision Frontier of Dark Matter Constraints from Direct Acceleration Measurements
For over a century, our understanding of dark matter has hinged on kinematic estimates derived from static snapshots of stellar positions and velocities. However, these methods are inaccurate for a time-dependent potential, and there are now many lines of observational evidence that show that our Galaxy has had a highly dynamic history. We have now entered an era where we can carry out precision time-series measurements of the accelerations of stars that live within the gravitational potential of our Galaxy.
I will discuss our comprehensive observational strategy to directly measure Galactic accelerations. Central to this discussion is our recent analysis of compiled pulsar timing data from which we were able to measure the Galactic acceleration for the first time, and derive fundamental Galactic parameters. Discernible differences in sub-structure exist among popular dark matter models on small scales, presenting testable nuances. I will discuss the potential for measuring dark matter sub-structure in the Milky Way by leveraging the diverse set of techniques we have developed, including pulsar timing, eclipse timing, and extreme-precision radial velocity observations. I will review our results from our multi-pronged observing campaign, and end by discussing synergies between Galactic dark matter constraints and constraints on theories of gravity.
Location: Chemistry 108
Time: 3:30PM – 5:00PM
Date: May 2nd, 2025

Physics Colloquium – Ned Budisa
2025-04-18 15:30 - 17:00
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 tool in systems bioengineering that combines synthetic biology, chemistry, biophysics, and genome manipulation. This approach enables enhanced protein biosynthesis, deeper insights into translation, and the creation of novel functionalities and new-to-nature proteins and other foldamer-scaffolds. Expansion of the genetic code results in proteins and cells with new properties, including site-specific functionalization through various bioorthogonal chemistries.
At the heart of this endeavor are aminoacyl-tRNA synthetases (aaRS), whose modified forms – paired with cognate tRNAs – form orthogonal translation systems (OTS) for precise incorporation of ncAAs, often via amber stop codons. Directed evolution under selective pressure is used to remodel the active aaRS center to accept specific ncAAs. Traditional gene libraries focus on the first-shell residues (<6 Å) and are constrained by the transformation limits of E. coli (~10⁸–10⁹ variants), often neglecting second-shell interactions (<9 Å). To overcome this, computational enzyme design and novel wet-lab strategies are driving the evolution of effective binding pockets and cellular compatibility with exotic chemicals.
I will illustrate these approaches using (i) directed evolution of enzyme pockets, (ii) adaptive laboratory evolution of the amino acid repertoire, and (iii) genomic integration of orthogonal translation machineries for synthetic cell design.
Finally, I will provide an overview of ncAAs that are valuable for biological spectroscopy and microscopy. These site-specifically incorporated ncAAs serve as vibrational, fluorescent, EPR, or NMR probes in cellular, organismic, and in vitro contexts. Over the last two decades, their use has provided unprecedented insights into protein structure and dynamics. Bioorthogonal reactions – in particular Click Chemistry – provide powerful tools to introduce labels or mimic post-translational modifications. Applications now include capturing transient interactions, tuning protein function and generating therapeutic agents such as covalent peptides and site-specific labeled antibody conjugates.
Location: Chemistry 108
Time: 3:30PM – 5:00PM
Date: April 18th, 202

Physics Colloquium - Sheng Ran
2025-04-11 15:30 - 17:00
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.

Physics Colloquium - Shaswat Sardesai
2025-04-04 15:30 - 17:00
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.

Spring 2025 APS Preview Talks
2025-03-14 15:30 - 17:00
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.

Physics Colloquium - David Hogg
2025-02-28 15:30 - 17:00
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.

Physics Colloquium - Geoffrey Bower
2025-02-21 15:30 - 17:00
Geoffrey Bower, Chief Scientist for Hawaii Operations, Academia Sinica Institute of Astronomy and Astrophysics, Project Scientist, Event Horizon Telescope Collaboration, Affiliate Graduate Faculty, University of Hawaii-Manoa, Dept. of Physics and Astronomy
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. Comparison with an unprecedented library of GRMHD simulations provides insights on the accretion and outflow properties. These results confirm that the gravitational lensing feature is a universal property of black holes, establishes the consistency of general relativity over three orders of magnitude in mass, and opens the door for future tests of gravitational physics, accretion, and jet formation.
The event flyer is available here.

Physics Colloquium - Scott Hertel
2024-12-13 15:30 - 17:00
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.
The event flyer is available here.

Physics Colloquium - Professor Scott A. Hughes
2024-12-06 15:30 - 17:00
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.
The event flyer is available here.

Physics Colloquium - Dr. Joshua "Shua" Sanchez
2024-11-22 15:30 - 17:00
Dr. Joshua “Shua” Sanchez, Postdoctoral Fellow, Department of Physics, MIT
Quantum Criticality and Magnetic Field-Induced Superconductivity
When electrons have strong interactions with each other, new quantum phases of matter emerge, such as magnetism, nematicity, charge order, and superconductivity. In these “Quantum Materials”, the microscopic interactions can be very difficult to probe and understand, yet they give rise to macroscopic properties that are easier to study and can be harnessed for new technologies.
In this talk, I will demonstrate how synchrotron x-ray techniques can be powerful probes to study the mysterious origin of strongly-correlated phases. I will discuss several recent projects at the Advanced Photon Source at Argonne National Laboratory, using a novel sample characterization platform that simultaneously combines x-rays, in-situ structural tuning, applied magnetic field, and electrical transport measurements. Our work yields new insights on two broad questions in high-temperature iron-based superconductors. (1) How does quantum criticality and nematicity relate to unconventional superconductivity? and (2) How can ferromagnetism and superconductivity coexist in one material, and how do they affect each other?
References:
(1) Sanchez, et al. Nature Materials 20, 1519–1524 (2021)
(2) Sanchez, et al. Science Advances 9, eadj5200 (2023)
The event flyer is available here.

Physics Colloquium - Catalin Picu
2024-10-18 15:30 - 17:00
Catalin Picu, Dept. of Mechanical, Aerospace & Nuclear Engineering, Rensselaer Polytechnic Institute
Soft Network Materials: Structure-Properties Relations
Many materials have a stochastic network of filaments as their main structural component and are referred to collectively as ‘network materials.’ This class includes all biological connective tissue, the extracellular matrix, the intra-cellular cytoskeleton, paper and cellulose-based products, nonwovens, as well as various molecular networks such as rubber, gels and thermosets.
This talk reviews the relation between the structure of athermal networks and the material-scale mechanical properties, focusing on identifying commonalities between these very diverse material systems. Properties of interest include the non-linear elastic response, the viscoelastic response, strength and toughness. The effect of inter-fiber adhesion on network mechanics will be also discussed. The talk provides a comprehensive overview of the mechanics of this broad class of materials.
The event flyer is available here.
