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

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.

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.

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.

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.

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.

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.

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.

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 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?

There will be no physics colloquium on April 21.

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!

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.