Connecticut’s oldest planetarium will soon be back in action. Once used for education and outreach for UConn faculty, students, and community members, the planetarium fell into disuse in the last several years, but Department of Physics Assistant Professor-in-Residence Matt Guthrie has been working hard with skilled facilities staff, including CLAS Facilities Team Leader Brett DeMarchi, to bring this piece of UConn history back into working order.
Two of UConn Physics Department’s undergrads, Rachel Cleveland and Nicholas Thiel-Hudson, have been recently selected as part of the 2024 cohort of UConn University Scholars! These students were selected based on the strength of their proposal. Graduation as a University Scholar recognizes a student’s extraordinary engagement with self-reflective learning and research or creative endeavors.
After years of disuse, the UConn Observatory, featuring a 16-inch optical telescope, is coming back into service. Physics faculty member Matt Guthrie, a driving force behind this rejuvenation effort spoke with UConn Today about the benefits offered by the Observatory both to students and to the community.
On October 14, 2023 40-50 members and friends of the UConn Physics department took part in the 51’st annual ascent up Mount Monadnock, near Jaffrey, New Hampshire. After the hike, the then-hungry hikers descended to the campground near Gilson Pond and enjoyed some well-earned refreshments.
INTRODUCTION The Department of Physics at the University of Connecticut (Storrs Campus) is pleased to invite applications for a tenure-track position in experimental or theoretical nuclear physics, with an emphasis on research in Quantum Chromodynamics or Nuclear Structure and Reactions, aligned with the scientific goals of major national user facilities such as the planned Electron-Ion […]
INTRODUCTION The Department of Physics at the University of Connecticut invites applications for a tenure-track position at the Assistant Professor rank, to start August 23, 2024. Candidates from all areas of astrophysics and cosmology are encouraged to apply. Applicants are expected to have a PhD in astrophysics or a closely-related field and to have established […]
The University of Connecticut, Department of Physics, is proud to announce that on October 20, 2023, Gérard Mourou, professor and member of Haut Collège at the École Polytechnique and A. D. Moore Distinguished University Professor Emeritus at the University of Michigan and 2018 Nobel Prize winner, will be presenting the 25th Distinguished Katzenstein Lecture.
About 20% of UConn students are supported by the Center for Students with Disabilities. The true percentage of students who need help is even higher. With so many students who require diverse ways of learning, how can faculty make sure their teaching is adequate, effective and inclusive for all students? In order to address this […]
Dear Friends of UConn Physics, Before highlighting some of the major events in the Physics Department during the past year, I need to sincerely thank Prof. Barry Wells for his leadership as Department Head for the past five years. Dr. Wells guided the department through the turbulent times of the COVID pandemic and resulting shutdown […]
Mirion Technologies, Inc. (https://www.mirion.com) formerly Canberra Inc., located in Meriden, CT, a worldwide leading company for manufacturing of electronics and nuclear detectors, established a partnership with our Physics department. In this partnership between our Physics department and a local industry, our students are encouraged to apply to spend a summer internship in the “real world” […]
A recent publication by Geoffrey Harrison, Tobias Saule, Brandin Davis, and Carlos Trallero from the Department of Physics, University of Connecticut is featured in Advances in Engineering. The publication presents a novel method for mitigating the bit-depth limit by increasing the phase precision of the Spatial Light Modulators (SLMs). The technique is based on adding […]
The UConn STARs visited Hartford High School on May 8th and 11th, 2023. We visited junior engineering students in the classroom of Mrs. Melissa Adams and the high school football team lead by Coach Jackson. We taught them all about quantum mechanics, solar telescopes, gravity, and of course electricity and they taught us as well. […]
Frederick Edward Steigert, of Westerly, RI passed away surrounded by the love of his family on Monday, May 29, 2023. He was the husband of Judith Carol (Lance) Steigert. Born in New York, New York on September 11, 1928, he was the son of the late Karl and Margarete (Shuppert) Steigert. Frederick was a dedicated […]
The Department of Physics is hosting UConn-NSF summer school on Parton Saturation and Electron Ion Collider (EIC). The School will take place in Storrs, from August 1 to August 10, 2023. The school chair is Professor Alex Kovner. The school website can be found at https://www.phys.uconn.edu/Conferences/saturation-eic/. The Electron-Ion Collider is the next big experiment in […]
Jeff Schweitzer passed away unexpectedly last year on May 31, 2022 in his home in Ridgefield, CT. Jeff was a faculty member in the physics department for 25 years (1997-2022). Jeff earned his B.S. in Physics from the Carnegie Institute of Technology (1967), and his M.S. (1969) and Ph.D. (1972) in physics from the Purdue […]
Galaxy clusters are the most massive objects in the Universe: a single cluster contains anything from a hundred to many thousands of galaxies, alongside collections of plasma, hot X-ray emitting gas, and dark matter. These components are held together by the cluster’s own gravity. Understanding such galaxy clusters is crucial to pinning down the origin […]
Promoting gender diversity and inclusion in the field of science, technology, engineering, and mathematics (STEM), the Connecticut Science Center’s Women in Science Initiative hosted a captivating outreach event led by UConn’s Sarah Trallero, Aslı Tandoğan, and Aislinn Daniels. This event took place on April 15th, 2023 at the Connecticut Science Center. In the outreach event, […]
A University chapter of Optica (formerly known as OSA), the largest professional society for Optics and Photonics, has started at UConn. Physics graduate students Zhanna Rodnova and Kevin Watson, and Electrical and Computer Engineering graduate student Gokul Krishnan started the chapter in the Fall of 2022 to help students, undergraduate, and graduate, learn more about […]
This year, international conferences have begun to come back into their pre-pandemic form. For the American Physical Society’s annual March Meeting, it was bigger than ever with over 12,000 participants in the world’s largest meeting ever devoted to physics. UConn showed strong as graduate students, postdoctoral fellows, research scientists, and faculty researchers attended the meeting […]
Graduate student Mitchell Bredice, Department of Physics, University of Connecticut
Kinetics, Nucleation, and Relaxation Dynamics of Ion-Seeded Nanoparticles
The recent interest in studying the adsorption and emission spectra of the hazy atmospheres of exoplanets stimulates the interest in clusters, small aggregates of atoms or molecules. The nucleation and dynamics of nanoparticles in the Earth’s atmosphere and their impact on the global climate and environment is another important area of research stimulating investigations of nucleation processes. However, how these small aggregates form is not wholly understood. Traditionally, nucleation of clusters or other phases is described through Classical Nucleation Theory. Although this theory has many discrepancies in describing the nucleation of submicron particles. In this work, we have performed molecular dynamics simulations of the nucleation of ion-seeded nanoparticles, specifically ArnH+ clusters, to investigate the microscopic mechanisms of nucleation from a gas or liquid phase. From these simulations, we have studied the stages of the nonequilibrium and equilibrium growth of ArnH+ clusters and analyzed the size distribution and internal energy relaxation of nascent clusters during different stages of their growth. The fundamental impact of the internal energy relaxation on the nonequilibrium nucleation of small ArnH+ clusters has been demonstrated. This analysis has generally been avoided in previous investigations due to assumptions of the equilibrium nature of the nucleation process. The results of our simulations showed that nanoparticles are formed in highly excited states, thus the cluster growth and relaxation are concurrent processes, and that relaxation of the cluster internal energy can delay cluster growth processes. To further investigate the internal energy relaxation, an ensemble of molecular dynamics simulations was performed for the detailed analysis of the average time evolution of kinetic, potential, and total energies of small ArnH+ clusters, and their kinetic energy relaxation. The results of the performed simulations have been explained through the use of a collisional Boltzmann equation describing the energy relaxation processes. Lastly, the general relationship between nonequilibrium growth and internal energy relaxation is discussed.
Graduate student Dharma Basaula, Department of Physics, University of Connecticut
This dissertation is focused on formulating, testing and validating a finite element method based computational framework for the evaluation and prediction of thermoelectric properties and performance of polycrystalline nanostructured materials and composites at mesoscale. The developed framework includes capabilities for building geometrical models of complex interfacial structures and, with the availability of appropriate input parameters, can be used predictively, providing new avenues for improvement of operational efficiency of nanoengineered thermo- electric materials and composites. The following benchmark problems were investigated on the first stage of this project, progressing from simple to more advanced cases: (a) effective Seebeck effect in a thermocouple; (b) Peltier heating and cooling at a single interface between two materials with different Seebeck coefficients; (c) coupled heat and electrical current transport through an anisotropic polycrystalline material. Excellent agreement with prior experimental or computational results was observed for the cases where such information was available. On the second stage, ‘digital twins’ for the experimental measurements of thermal and electrical conductivities, and Seebeck coefficient in a material sample were developed within the same computational framework, allowing one to evaluate its thermoelectric figure of merit ZT(T). This approach was tested on three popular nanocrystalline thermoelectric systems: n-type Si, n-type Si0.80Ge0.20, and p-type BiSbTe, providing excellent agreement with previously measured values of ZT(T) and highlighting the importance of interfacial properties for making accurate predictions of the material thermoelectric performance and efficiency. Finally, on the third stage, the sensitivity of sample thermoelectric properties and the resulting ZT(T) to variations in the system microstructure, morphology and input material parameters was elucidated.
Graduate student Bochao Xu, DEpartment of Physics, University of Connecticut
Scanning SQUID Investigation of Time-reversal Symmetry Breaking in Exotic Quantum Materials
Spontaneous breaking of time-reversal symmetry in condensed matter systems arises from correlated electronic arrangements leading to various quantum phenomena, such as ferromagnetism, unconventional superconductivity, and topological states of matter. However, these underlying electronic orders are often difficult to detect experimentally if the magnetism associated with the time reversal symmetry breaking is weak. In such cases, the subtle magnetization and complex domain structure call for investigation by experimental techniques with both high magnetic sensitivity and high spatial resolution. In this dissertation talk, I will discuss my exploration of time-reversal symmetry breaking in two systems: a magnetic Weyl semimetal and a Kagome material detected using scanning superconducting quantum interference device (SQUID) microscopy. Both materials exhibit intriguing magnetic structures which were not detectable by the bulk measurements. We show that the Weyl semimetal hosts a tunable heterogeneous domain structure that is likely linked to its unconventional electronic properties. Additionally, our local probe reveals a ferromagnetic-like state in the Kagome material system, contributing evidence to the highly controversial problem within the community regarding the existence of time-reversal symmetry breaking and its underlying mechanism in this material. These results highlight the significance of quantum sensing in advancing the frontier of new correlated materials, and showcase these materials as an ideal playground for studying the magnetism-electrons interplay.
Graduate student Hanzhen Ma, Department of Physics, University of Connecticut
Cooperative radiation has been a long-standing open question in many-body physics. The dipole-dipole interaction between the atoms gives rise to the all-to-all coupling, and can lead to novel collective phenomena. In this talk, I will introduce an integrated method for studying cooperative radiation in many-body systems. This method allows us to study extended systems with arbitrarily large number of particles, and can be formulated by an effective, nonlinear, two-atom master equation that describes the dynamics using a closed form. We apply this method to various systems to demonstrate the appearance of superradiance, subradiance, collective Lamb shift, spin-squeezing and so on. We investigate how the properties of radiation depend on system parameters such as the optical depth and geometry of the system.
Graduate Student Jonathan Smucker, Department of Physics, University of Connecticut
Charge Transfer Collisions Involving Nano-Particles or Large Molecules
Charge transfer has been a popular field of study since the advent of quantum mechanics due to its applications to astrophysics, plasma physics, atmospheric science, chemistry, and fundamental physics. Various experimental and theoretical studies have been developed for charge transfer in atom-ion collisions and the process is generally considered well-understood in these systems. However, the models developed for atom-ion collisions are not sufficient to explain charge transfer processes in systems with large molecules, such as fullerenes. The added degrees of freedom in these more complex systems bring many theoretical complications but also many opportunities to explore new types of charge transfer. In this dissertation talk, I will present several models that we have developed to explain different charge transfer processes involving fullerenes. These models are the first to accurately predict many existing experimentally measured charge transfer cross-sections.