Nearly thirty years after the Nobel-prize-winning discovery of the exoplanet 51 Pegasi b, astronomers have discovered thousands of planets outside the solar system, and the field of exoplanetary astronomy has shifted from purely being driven by discovery to performing demographic analysis, and detailed characterization of properties like mass, radius, and atmospheric composition. However, even today, basic questions remain, like “why do some systems end up looking like the Solar System with orderly co-planar architectures, with small planets close-in, and giant planets orbiting far from their stars, while others, like the so-called Hot Jupiters, are dramatically different?” My team and I are tackling this question from both sides: understanding the evolutionary origins of hot Jupiters and understanding the properties of compact multi-planet systems. Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and Kepler/K2 missions, we are working to find keystone planetary systems around bright stars (those well suited for atmospheric observations) that can help address specific questions about planet formation and evolution. I will review our efforts to discover and characterize hundreds of hot Jupiters while investigating the compact architectures of small rocky planets. Finally, uncertainty in planetary orbital solutions for hundreds of planets have accumulated since their initial detection to the extent that they are not accessible with the James Webb Space Telescope (JWST) to study their atmospheres. I will also discuss how we are addressing this problem on a large scale to make hundreds of planets accessible for JWST.

Observing neutrinoless double-beta decay (0νββ) would confirm the neutrino has a Majorana nature and offer critical evidence to understanding the universe’s matter/antimatter asymmetry. The LEGEND collaboration targets half-lives greater than T1/2>1028 years using the high-purity germanium (HPGe) detectors enriched in the isotope 76Ge. Achieving this unprecedented sensitivity – 18 orders of magnitude beyond the age of the universe – requires a detector environment with exceptionally low background radiation. While HPGe detectors are central to the measurement, sensitivity to 0νββ decay hinges on the scintillating materials surrounding them to actively detect and reject ambient background radiation.

This seminar explores the critical role of radiopure scintillating materials in LEGEND, focusing on poly(ethylene-2,6-naphthalate) (PEN). We will present technical results detailing the radiopurity, scintillation performance, and mechanical stability of these materials, highlighting their successful deployment as both a structural element and an active background veto in LEGEND-200. Furthermore, we will detail ongoing efforts in additive manufacturing to realize complex, ultra-pure components for the future LEGEND-1000 phase.

Beyond these technical results, we will discuss the opportunities of cross-disciplinary collaboration, bridging the fields of material science and particle physics to solve unique and complex challenges vital for fundamental discovery. This talk will conclude with a discussion on the communication journey of working on an “enabling technology” within the framework of a large-scale collaboration, with insights on how to effectively communicate the profound scientific impact of support technologies.

Magnetism is the posterchild of how the interplay between electron-electron interactions and quantum physics promotes novel macroscopic phenomena. Historically, the evolution of our understanding of magnetism has been related to the discovery of new paradigms in condensed-matter physics, as exemplified by the connections between antiferromagnetism and Mott insulators, spin glasses and non-ergodic states, and spin liquids and fractionalized excitations. Recently, a new framework proposed to classify magnetic phases brought renewed interest in unconventional magnetic states, which are qualitatively distinct from ferromagnets and standard Néel antiferromagnets. Among those, altermagnetic phases have been met with enthusiasm by the scientific community, as they display properties found in both ferromagnets (like the splitting of electronic bands with opposite spins) and conventional antiferromagnets (like the absence of a net magnetization). Formally, what distinguishes these three different magnetic states are the crystalline symmetries that, when combined with time reversal, leave the system invariant. In the case of altermagnets, because these symmetries involve rotations, the system is endowed with unique properties such as nodal spin-splitting and piezomagnetism. In this talk, I will introduce the concept of altermagnetism and discuss its connection to long-standing problems in the field of quantum materials, such as multipolar magnetism and electronic liquid-crystalline phases. I will also present the predicted experimental signatures of altermagnetic order in thermodynamic and transport properties, and show that altermagnets provide a fertile ground to realize non-trivial topological and superconducting phenomena in quantum materials.

Observations spanning multiple astronomical scales point to the existence of an unknown form of matter, dubbed “dark matter”, that constitutes over 85% of the mass of most galaxies. Recent theoretical insights into the possible nature of dark matter and how it interacts with normal matter have inspired a wide range of experimental efforts aimed at directly detecting dark matter. As part of this effort, we are developing a small-scale experiment to search for multiple well-motivated “ultralight” dark matter candidates, placing stronger bounds than are currently possible with high-cost and/or large-scale efforts. The core enabling technology relies on microwave cavity readout of mechanical motion in superfluid helium. I will tell you about the experiments that have led up to where we are now, and our current efforts with regards to this table-top dark matter search.

The detection of GW170817 enabled us to track down and watch the cataclysmic event in multiple wavelengths of light, allowing us to scrutinize the source of these cosmic ripples for the first time. This discovery provided the first solid evidence that neutron-star smashups are the source of much of the Universe’s gold, platinum, and other heavy elements. With a single event, we were able to answer fundamental questions in general relativity, cosmology, nuclear physics, and astrophysics. However, other aspects of the story, as revealed by these events, are still shrouded in mystery. For astronomers and physicists across disciplines, this is a fascinating time to be alive.

The weak force of nature uniquely allows quarks to change flavor, resulting in the transformation of nuclei known as nuclear beta decay. Currently, measurements of the weak mixing of quarks are in tension with the Standard Model’s description, a discrepancy referred to as the “Cabibbo Angle Anomaly.” As the simplest nucleus to undergo beta decay, the neutron has emerged as a system which can provide a competitive measurement and shine light on this anomaly if experimental uncertainties in the neutron dataset can be improved. The Nab experiment at the Spallation Neutron Source employs a novel and robust approach to improve decay correlation measurements by observing the full momentum phase space in neutron beta decay accessible above detection thresholds. The tight kinematic constraints from the experiment have recently been used to place first limits on a new hypothesized excited state of the neutron, suggested to address experimental disagreements in neutron lifetime measurements. In this presentation, I will describe the working principles of the experiment, present early results from first physics data-taking, and discuss the outlook for Nab and its upgrade pNAB (polarized Nab) to perform world-leading measurements of neutron decay correlations and improve our understanding of quark mixing in the weak interaction.

All living cells are bounded by envelopes that protect them from the environment and confer their sizes and shapes. These shapes help cells to spatially organize their internal biological processes, allowing them to divide and faithfully segregate genetic material to each daughter. Yet, we still know very little about how cells obtain and control cell shape, even in the arguably simplest and best understood organism: the rod-shaped Escherichia coli. To resist a high intracellular osmotic pressure, bacteria and many other single-celled organisms are surrounded by a cell wall, an elastic, covalent meshwork of sugars and peptides. For walled cells to grow, they must enzymatically cut cell-wall bonds while inserting new cell-wall material to prevent envelope rupture. In some bacteria and many fungi and plants, the process of cell-wall remodeling is limited to the tip of the cell, where intracellular pressure and enzymatic cell-wall fluidization drive growth of the rod, akin to glass blowing. However, in E. coli and many other rod-shaped bacteria, cell-wall remodeling happens all along the cylindrical part of the cell, while the poles remain inert (new poles being constructed at mid-cell during division). How do cells control a straight rod-like cell geometry with a well-defined diameter, all the while increasing cell length at a rate that accommodates biomass growth? While the ultimate answers to these questions remain to be found, we have made important progress in the past two decades. For example, i) curved cytoskeletal polymers sense cell-envelope curvature and reenforce cylindrical geometry, ii) mechanical stress affects envelope growth locally, and iii) the ratio between cell-surface area and biomass emerges as a controlled variable, thus coupling the global rate of envelope growth to the rate of biomass growth. I will present these and other findings, illustrate the importance of experiments and theory, and present future directions.

Dark matter is thought to make up 25% of the universe. Dark sector particles (DSP) do not interact through the known forces but could be weakly coupled to Standard Model particles through a portal or a mediator (Dark Messenger) that could provide access to the dark matter world. Many searches for these particles at an accelerator thus far seem to face a ceiling that the sensitivity reach is greatly limited, beyond statistical effects. DAMSA (DArk Messenger Searches at an Accelerator) is an extremely short baseline, table-top scale experiment that aims to break through this limit. The experiment plans to take advantage of high beam powers available at various accelerator facilities around the world, including the PIP-II LINAC under construction at Fermilab near Chicago, an essential element in providing the necessary high flux proton beams to the $3.5B U.S. flagship neutrino experiment, DUNE. In this talk, I will describe the DAMSA experiment and discuss the current status and plan for DAMSA, as well as its expected sensitivity reach on the search of the Axion-Like Particle, a dark messenger, as a benchmark physics case.

There will be no colloquium on October 6.

When a nucleus is permanently deformed, it exhibits a characteristic rotational band, in which the excitation energies of a state with spin I is proportional to I(I+1). It also shows enhanced electromagnetic transition strengths as well as large quadrupole moments. Moreover, it has also been well known that nuclear deformation significantly affects low-energy nuclear reactions. In particular, heavy-ion fusion reactions at energies around the Coulomb barrier are sensitive to nuclear deformation, and there have been many attempts to determine deformation parameters of a nucleus. In recent years, there has also been increasing interest in probing nuclear deformation in relativistic heavy-ion collisions.

In this talk, I will discuss recent theoretical developments in low-energy heavy-ion reactions, putting emphasis on nuclear deformation. This includes i) a new attempt to visualize nuclear scattering and ii) an emulator for multi-channel scattering. I will also discuss the role of shape dynamics in relativistic heavy-ion collisions.

Although the astrophysical origin of elements is a longstanding mystery, neutron capture processes are known to be a crucial mechanism by which nucleosynthesis can overcome the repulsive forces associated with adding another proton to a nucleus. Studies have identified at least three neutron capture processes believed to be taking place in astrophysics: the slow (s), rapid (r), and intermediate (i) neutron capture processes. Not only are the site(s) of the r and i processes under active study, but open questions remain regarding how much each of these contributed to the overall enrichment of stars such as our Sun. In particular, the r process synthesizes exotic and unstable nuclei that have yet to be probed in terrestrial experiments. Thus r-process studies must consider how uncertainties in the nuclear physics data propagate to the interpretation of observables. In this talk I will discuss how observables such as stellar abundance patterns and signals from multi-messenger events such as MeV gamma rays can be used to inform r-process studies. I will show how recently reported nuclear masses from experiments and cutting-edge nuclear theory change our picture for the abundance of key elements (e.g. gold) produced in sites such as neutron star mergers. I will also discuss new applications of machine learning to nucleosynthesis problems. Novel, interdisciplinary work at the intersection of observation, experiment, theory, and computational science are key to carving out the new ideas and tools needed to modernize heavy element nucleosynthesis studies.

Dominant narratives in introductory physics education often focus on student preparation in mathematics. Students who have not reached a certain level of proficiency as determined by math placement tests are often labeled as underprepared. In this presentation, I will challenge this narrative by reframing the notion of underprepared. Indeed, many physics departments and instructors are underprepared to support the students accepted into their institutions. The Transforming Introductory Physics Sequences to Support all Students (TIPSSS) Network is a network of physicists developing curricular materials, transforming courses, and research the effectiveness of these efforts to help departments meet the needs of their physics students, regardless of the students’ prior mathematics preparation. I will present and overview of the TIPSSS activities and also preliminary findings from the TIPSSS studies.

Fusion energy promises to be a transformative, long-term solution to global energy needs—offering abundant, safe, and carbon-free power. This talk will introduce the fundamentals of fusion, the technical challenges of harnessing it for practical energy production, and the strategies being pursued to overcome these challenges. The talk will highlight recent progress in both public and private sector efforts and outline the path toward a fusion pilot plant. I will highlight the challenges in plasma physics, plasma-materials interaction, and condensed matter/materials science that represent opportunities for collaboration between UT and ORNL.

There is no colloquium on September 1.

With the completion of the Standard Model (SM), Particle Physics stands at a crucial point, where a successful theory framework is faced with a collection of mysteries, contradictions, and unexplained curiosities. Physics at today’s high energy particle collider, the Large Hadron Collider, is a mixture of testing every prediction of the SM and directly searching for signatures that would require a rewrite of our textbooks and symmetries. This talk will describe the broad motivation for my research program today with a focus on unconventional collider signatures, machine learning, and the technical challenges for a future muon collider – a program designed to address both the questions the SM doesn’t answer, and those it doesn’t even ask.

Have you ever left a colloquium or a seminar and thought to yourself “that was interesting, but it wasn’t physics”? If so, you are in good company, because there has long been disagreement in our community about which research specialties belong to the canon of physics and which do not, particularly when it comes to hiring faculty members into physics departments to train PhD students. In this talk, I discuss some aspects of this debate from the founding of the American Physical Society to the present day. Examples include a field that was once a part of physics but is not anymore; a field that was once “not physics” but is definitely so today; and a field whose status as “physics” remains unsettled in the minds of many.

Join us for UT Physics Honors Day as we recognize outstanding students, faculty, and staff! As the final colloquium of the spring, we’ll move to Room 262 in the Student Union to present our annual awards.

Since the times of Henry Cavendish and John Mitchell, the strength of gravity has been measured by comparing it to the reaction of a calibrated mechanical spring. While in the last 60 years planetary measurements (with natural and artificial bodies) have provided remarkable accuracy at large distance, measurements in the lab have continued to rely various incarnations of the good old mechanical springs, in many cases resulting in superb experiments and results.

In this talk, I will explore a number of drastically different techniques recently developed specifically to tackle the short distance regime, where many theories suggest something exotic may be happening. This will be a trip into AMO, high resolution nuclear spectroscopy, and neutron scattering. While science results are gradually appearing, I hope to convince the audience that, as is often the case with new techniques, a new and exciting array of questions and applications are also emerging!

There will be no physics colloquium on April 21.

The James Webb Space Telescope is the culmination of thirty years of planning, twenty years of construction, and eleven billion dollars of funding — and it was designed specifically to perform the first systematic exploration of stars, galaxies, and black holes in the early universe. Luckily for us, this first systematic exploration is happening now; in our lives. I will discuss some of the early, stunning, and sometimes tentative, discoveries we have made in Webb’s first deep fields, measuring the ancient light from early galaxies and black holes originating near the edge of the observable universe. I will in particular discuss the latest observational constraints on the new, mysterious, very bright, surprisingly common, and so-far-inscrutable objects at the edge of the universe: “little red dots”. Are they overly massive and/or old galaxies, `overmassive` supermassive black holes arising far earlier than expected – or perhaps something else entirely?

Superconductivity and superfluidity are some of the most striking macroscopic manifestations of quantum mechanics. In recent years strong superconductivity has been observed in systems in which the electrons behave as extremely heavy particles, i.e., have a very large effective mass. This is somewhat surprising given that the conventional theory of superconductivity predicts that the ability of a system to carry a supercurrent decreases as the effective mass of the electrons increases. In this talk I will discuss how robust superconductivity and superfluidity can be present in multi-band systems in which the effective mass of the electrons is infinite due to the quantum metric of the electronic states. This contribution is one more example of the deep connection between quantum mechanics and superconductivity. I will then discuss the relevance of this contribution for systems like twisted bilayer graphene.

The era of time domain and multi-messenger astronomy is not only leading to the development of a much broader set of detectors and instruments for astrophysical observations, but is also providing the means for astronomy to tie directly to cutting-edge studies in physics. In this manner, fundamental physics (theory and experiment) coupled with a strong theoretical understanding of astrophysical phenomena (guided by high-performance computing simulations) can tie directly to the amazing new observations in astronomy. Here we discuss how physics, astrophysical models, and observations can not only help astronomy probe fundamental physics but guide the needs for next-generation astrophysical missions.

There are approximately 300 stable and 3,000 known unstable (rare) isotopes. Estimates are that over 7,000 different isotopes are bound by the nuclear force. It is now recognized that the properties of many yet undiscovered rare isotopes hold the key to understanding how to develop a comprehensive and predictive model of atomic nuclei, to accurately model a variety of astrophysical environments, and to understand the origin and history of elements in the Universe. Some of these isotopes also offer the possibility to study nature’s underlying fundamental symmetries and to explore new societal applications of rare isotopes. This presentation will give a glimpse of the opportunities that arise at the Facility for Rare Isotope Beams (FRIB) that started operations at Michigan State University in 2022.

Rapid progress in the experimental control and interrogation of molecules is enabling new opportunities for investigating the fundamental laws of our universe. In particular, molecules containing heavy, octupole-deformed nuclei, such as radium, offer enhanced sensitivity for measuring yet-to-be-discovered parity and time-reversal violating nuclear properties. In this colloquium, I will present recent highlights and perspectives from laser spectroscopy experiments on these species, as well as discuss the relevance of these experiments in addressing open problems in nuclear and particle physics.

In this talk, I will briefly introduce the molecular beam epitaxy (MBE) growth mechanism and then focus on my research, which centers on the MBE growth of quantum materials, spanning from topological materials to interfacial superconductors. I will talk about two solid-state phenomena with zero resistance: the quantum anomalous Hall (QAH) effect and the interface superconductivity. The QAH insulator is a material in which the interior is insulating but electrons can travel with zero resistance along one-dimensional conducting edge channels. Owing to its resistance-free edge channels, the QAH insulator is an outstanding platform for energy-efficient electronics and spintronics as well as topological quantum computations. With many efforts, we were the first to realize the QAH effect in MBE-grown Cr- and V-doped topological insulator (TI) thin films. I will briefly talk about the route to the QAH effect and then focus on our recent progress on the high Chern number QAH effect and three-dimensional QAH effect in MBE-grown magnetic TI multilayers. Finally, I will talk about the interfacial superconductivity in MBE-grown magnetic TI/iron chalcogenide heterostructures. Moreover, the magnetic TI/iron chalcogenide heterostructures fulfill the three essential ingredients of chiral topological superconductivity, i.e. ferromagnetic, topological, and superconducting orders, and thus provide an alternative platform for the exploration of chiral Majorana physics towards the scale topological quantum computations.

Core-collapse supernovae and neutron-star mergers produce copious amount of neutrinos, which impact evolution of these astrophysical sites as well as the element synthesis they may host. Collective oscillations of these neutrinos represent emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. In this talk, after a brief introduction, it will be shown that neutrinos exhibit interesting entanglement behavior in simplified models of those oscillations. Also attempts to study this behavior using classical and quantum computers will be described.

My research focuses on understanding the implications of the Standard Model of particle physics in the formation of the basic building blocks of nature. This model describes three of the four fundamental forces of nature. The opaquest of these is the strong nuclear force which is responsible for the formation of all atomic nuclei. We know that this force is fundamentally described in terms of the theory of quarks and gluons, which is known as quantum chromodynamics (QCD). My research focuses on the development and implementation of novel mathematical and computational techniques to study the emergence of nuclear phenomena directly from QCD. In this talk, I review some of the key ideas driving the field of nuclear physics.

Raising the superconducting transition temperature (Tc) to a point where applications are practical remains one of the most critical challenges in condensed matter physics today. Recent advances in sulfur hydrides have renewed hope of reaching room temperature superconductivity, though the extremely high-pressure requirement limits their practical applications. In this talk, I will show our work on an alternative route to achieve high-temperature superconductivity. By the epitaxial growth of single-layer superconductors on tailored substrates, the superconducting Tc can be enhanced through interfacial interactions optimized to enable 1) charge transfer doping and electron-phonon coupling, 2) coupling to quantum fluctuations of the substrate, and 3) dynamic control via light-matter interactions. Using FeSe grown on SrTiO3(001) substrate as an example, I will show that growth on different terminations of the SrTiO3 substrate can enable the control of charge transfer doping and, in turn, superconducting Tc. Similarly, the substitution of isovalent sulfur (S) or tellurium (Te) in FeSe, equivalent to applying positive (negative) chemical pressure, can turn the interfacial atomic-scale geometry that controls the strength of electron-phonon coupling, thus the superconducting Tc. Finally, I will show that UV light can lead to enhanced superconductivity in the FeSe/SrTiO3, which is also persistent. These findings indicate that epitaxial Fe-chalcogenide heterostructures are a highly tunable quantum system and shed light on the mechanism of high-temperature superconductivity in Fe-based superconductors.

The department will share good news and plans for the future, followed by a Q&A session with faculty, staff, and students.