Department of Physics & Astronomy "Colloquia and Seminars" Series

Virtual or R-150, Hilbun Hall, Mississippi State University

Fridays @ 3:00 PM

Apr. 4^th, 2025 Dr. John A. Goree, Physics & Astronomy Department, University of Iowa

   My Experience As an Expert Witness in a Murder Trial

  Host: Dr. Chuji Wang

  Instruction: In-person in Hilbun R-150

  Abstract:

       In 2016, a businessman fell to his death in Des Moines, Iowa under suspicious circumstances. A suspect’s account of what happened seemed to be physically unlikely, leading a detective at the Des Moines Police Department to contact the Department of Physics and Astronomy at The University of Iowa to seek expert assistance. I volunteered, and performed some work, including simple calculations about potential and kinetic energy of a falling body, and comparing to literature for forensic biomechanics. Later, in April 2024, there was a trial, where I testified for the prosecution, and I was cross-examined by the defense. I will describe how my project and trial testimony had much in common with a professor’s job of doing research and lecturing, but with some important differences.

Past Colloquia/Seminars

Mar. 28^th, 2025 Dr. Anne Staples, Department of Mechanical Engineering, Virginia Tech

   Mechanisms of Insect Respiration

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       Insect respiration is characterized by the rapid transport of respiratory gases and efficient exchange with the environment, achieved through a branching network of tracheal tubes that directly supply oxygen to cells. This unique arrangement obviates the need for blood as an intermediate oxygen carrier, contributing to the remarkable metabolic range of insects—the highest in the animal kingdom. Insects’ microscale transport strategies offer compelling design principles for microfluidic technology, particularly in the realms of gas microfluidics and tissue engineering. Despite this significance, the fundamental mechanisms governing insect respiration remain limited. In this talk, I will present a series of mathematical, computational, and microfluidic models of insect respiration that recapitulate key aspects of insect respiratory function. I will then describe our ongoing work to develop insect-inspired, pulse-powered microfluidic infusion pumps. This emerging platform technology has the potential to drastically reduce the size and complexity of ambulatory infusion systems for delivering insulin, chemotherapy, vaccines, and other therapeutics.

Mar. 21^st, 2025 Dr. Kurtis Williams, Physics & Astronomy Department, East Texas A&M University

   White Dwarfs as Whirling Dervishes: The Frequency of Rapid Rotation

  Host: Dr. Donna Pierce

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       White dwarfs are the compact remnants of stellar evolution for over 98% of all stars. As such, white dwarf studies provide crucial forensic information into the complex physics present during stellar death. In particular, white dwarf rotation encodes information on processes such as stellar merger history and angular momentum transport during post main sequence evolution. Recently, due in part to precision time series data from satellites and in part to increased efforts in wide-field time domain surveys, interest in white dwarf rotation studies has grown significantly. I’ll present results from an ongoing effort to detect rapid rotation ( 4ish hr period) via photometric variability in multiple samples of white dwarfs including massive magnetic white dwarfs and cool, normal-mass white dwarfs that some suspect of being merger remnants. Each sample has well-defined selection criteria to minimize selection bias and includes WDs as faint as V∼18 in order to cover volumes beyond 100 pc. I’ll discuss both the fraction of each sample exhibiting rapid rotation and present the resulting rotational distributions at these short periods. I end by conjecturing on the interpretation of our results and some necessary follow-up studies to confirm our findings.

Mar. 14^th, 2025 Spring Break: No Colloquium; Enjoy :) and be Safe!

Mar. 7^th, 2025 Dr. Luwani Ndukum, Engineering Management, Intel Corporation

   The Physics Paradox: Exploring Exciting Career Pathways beyond Academia, from Physics to Industry

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       Only about 15% of Physics PhDs end up in tenure-track faculty positions. Physics PhDs are in high demand across various industries, yet many students and professionals are unaware of the vast career opportunities available. Join me on a journey from Physics to industry, as I share my personal experiences and insights. I'll discuss the skills, experiences and knowledge that make physics graduates highly sought after, and highlight exciting career pathways in industry available to physics graduates. Learn how to leverage your physics degree for a rewarding career in industry, and gain insights on how to prepare for a successful transition.

Feb. 28^th, 2025 Dr. Sukanya Chakrabarti, Physics & Astronomy Department, The University of Alabama in Huntsville

   The Precision Frontier of Dark Matter Constraints from Direct Acceleration Measurements

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       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. Recent technological advancements now empower us to carry out precision time-series measurements of the acceleration 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 initial results from our multi-pronged observing campaign, and end by discussing synergies between Galactic dark matter constraints and constraints on theories of gravity.

Feb. 21^st, 2025 Dr. Anatoli Afanasjev, Physics & Astronomy Department, Mississippi State University

   Atomic nuclei in covariant density functional theory: from nodal structure of the wave function to global improvement of functional

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       The atomic nucleus is described as a system of nucleons which interact via the exchange of mesons in covariant density functional theory (CDFT). This is the state-of-the-art relativistic version of density functional theory. I will start my presentation from basis features of the CDFT and the illustration of its applicability to different physical phenomena. Then, I will focus on the nodal structure of the single-particle wave functions as a tool for an understanding of different physical phenomena. Its impact on the evolution of charge radii in different isotopic chains and on the formation of cluster structures in light nuclei will be discussed in detail. Finally, our efforts on global improvement of covariant energy density functionals and its global consequences will be discussed.

Feb. 14^th, 2025 Mr. Muhammad "Farouk" Yusuf , Physics & Astronomy Department, Mississippi State University

   Variational Quantum Algorithms: Two Use Cases: Variational Quantum Eigensolver and Variational Quantum Linear Solver

  Host: Dr. Gautam Rupak

  Instruction: In-person in Hilbun R-150

  Abstract:

       Variational Quantum Algorithms (VQAs) represent a significant advancement in quantum computing, offering solutions for solving intricate problems in physics, chemistry and beyond. This presentation focuses on two key use cases of VQAs: the Variational Quantum Eigensolver (VQE) and the Variational Quantum Linear Solver (VQLS). The VQE is applied to elastic scattering simulations on quantum computers, employing a parametrized quantum circuit with classical optimization techniques to precisely evaluate energy states. This method's efficacy is demonstrated in the context of the Busch-Englert-Rzazewski-Wilkens (BERW) formula, providing quantum solutions for scattering phase shifts in an interacting harmonic trap. Meanwhile, the VQLS is employed to solve linear equations in quantum physics, particularly through simulating a two-site linear device with quantum leads. This application highlights its potential in studying electron transport in nanoscale systems, such as quantum dots, molecular junctions, or nanowires, outperforming traditional methods like the Harrow-Hassidim-Lloyd (HHL) algorithm. Both VQE and VQLS are shown to be adaptable to Noisy Intermediate-Scale Quantum (NISQ) devices, making them practical for current quantum hardware. Through detailed methodologies, comparative analyses, and algorithmic optimizations, this work demonstrates the utility of VQAs in nuclear, condensed matter, and computational physics. It also explores their potential to advance quantum computing beyond the NISQ era, paving the way for fault-tolerant, large-scale quantum systems.

Feb. 7^th, 2025 Dr. Julie Roche, Physics & Astronomy Department, Ohio University

   Tomography of the Proton

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       The proton is a composite particle made up of quark and gluon. The details of how gluons and quarks are confined within the proton remain surprisingly mysterious. For example, the elegant theory that governs the interaction of gluons and quarks, Quantum ChromoDynamics (QCD), cannot be solved analytically at the proton size scale. Experimentally, while the spatial and momentum distribution of quarks and gluons inside the proton are known, the correlation between the two is not. Generalized Parton Distributions (GPDs) were introduced in 1995. They encode this correlation. In this talk, I will review the worldwide data of this emerging field of study. I will also emphasize the importance of the precision experimental approach implemented by my JLab collaboration.

Jan. 31^st, 2025 Dr. Adam McKay, Physics & Astronomy Department, Appalachian State University

   Using JWST NIRSpec to Study the Volatile Composition of Centaurs

  Host: Dr. Donna Pierce

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Centaurs are primitive leftovers from the formation of the solar system and are thought to be the dynamical precursors to Jupiter Family Comets (JFCs). Therefore, their volatile composition holds clues to the physics and chemistry of the early solar system as well as the degree of compositional evolution experienced by JFCs. However, their large distances from the Sun make observations of volatile gases in centaurs challenging. Moreover, the mechanisms driving Centaur activity are still poorly understood. The launch of the James Webb Space Telescope (JWST) enabled new observational capabilities that can help answer these questions about Centaur composition and activity. We observed six active centaurs with the NIRSpec instrument on JWST to characterize their volatile composition, specifically in terms of H2O, CO2, and CO. We will present an overview of results from this program to date, including the first detection of CO2, the first characterization of CO2 and CO jets, and the first detection of isotopologues of CO and CO2 in a centaur.

Jan. 24^th, 2025 Dr. Ram Babu Yadav, Biological & Physical Sciences Department, South Carolina State University

   Laser Spectroscopy of Proton-halo Structures in ²²Al and ²³Al

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       Proton-halo structures in the ground states of ²²Al and ²³Al have so far been hinted to occur by theory and scattering experiments. Measurements of the changes in mean-square nuclear charge radii 𝛿⟨𝑟2⟩, and nuclear electromagnetic moments, can provide essential experimental knowledge to understand the structure of these nuclei. Additionally, these results will establish an important benchmark for the development of many-body methods. Moreover, their high sensitivity to charge-symmetry-breaking forces makes them of particular interest to test modern descriptions of the nuclear force. In this talk, I will present the first physics results from the Resonant Ionization Spectroscopy Experiment (RISE), recently developed at the BEam COoler Laser spectroscopy facility (BECOLA), at the Facility for Rare Isotope Beams (FRIB), at Michigan State University. Measurements of the hyperfine spectra of the 3p ²P_1/2 → 5s ²S_1/2 atomic transition in ^{22, 23, 24, 24m, 25}Al were obtained, allowing – for the first time – a charge radius extraction of aluminum isotopes all the way to the proton dripline. The preliminary results from the isotope shift analysis of these neutron-deficient aluminum isotopes and their implications for our understanding of the nuclear structure in the region will be discussed, including the proposed proton-halo candidates ^{22, 23}Al.

Jan. 17^th, 2025 Dr. Vladimir Khachatryan, Department of Physics, Indiana University Bloomington

   Overview of the proposed Solenoidal Large Intensity Device (SoLID) and its physics programs at Jefferson Lab

  Host: Dr. Wenliang (Bill) Li

  Instruction: In-person in Hilbun R-150

  Abstract:

       The Solenoid Large Intensity Device (SoLID) is a new experimental apparatus planned for Hall A at the Thomas Jefferson National Accelerator Facility (JLab). SoLID can enhance the physics output of JLab in a number of exciting areas, based on combining large angular and momentum acceptance with the capability of handling very high data rates at high luminosity. Together with other approved high-impact physics experiments, the apparatus will be capable of pushing JLab to a new limit at the QCD intensity frontier that will exploit the full potential of its 12 GeV electron beam.
       In this talk, I will give an overview of the rich physics program that can be realized with SoLID, mostly focusing on the program's three science pillars. Namely, (i) the tomography of the nucleon in 3-D momentum space from Semi-Inclusive Deep Inelastic Scattering (SIDIS), (ii) expansion of the phase space in the search for new physics and novel hadronic effects in Parity-Violating Deep Inelastic Scattering (PVDIS), and (iii) a precision measurement of J/Psi meson production at threshold that will probe the gluon field and its contribution to the proton mass and quantum anomalous energy. I will summarize my presentation by discussing some of the approved experiments of the SoLID program.

Upcoming Colloquia/Seminars

Apr. 11^th, 2025 Dr. Mark Novotny, Physics & Astronomy Department, Mississippi State University

   TBC

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

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Apr. 18^th, 2025 Easter Break: No Colloquium; Enjoy :)!

Apr. 25^th, 2025 Dr. Elena Litvinova, Department of Physics, Western Michigan University

   TBC

  Host: Dr. Anatoli Afanasjev

  Instruction: In-person in Hilbun R-150

  Abstract:

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May 2^nd, 2025 Dr. Shane Huston, Department of Biological Sciences, Vanderbilt University

   TBC

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

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May 6^th, 2025 ***** End of the 2025 Spring semester; All the best with final exams to whom it concerns! *****

2024 Fall Colloquia/Seminars Series

Nov. 29^th, 2024 ***** Happy & Safe Thanksgiving Break as well as Holidays Season *****

***** End of the 2024 Fall semester; Heartfelt wishes for Healthy and Properous New Year 2025 :)! *****

Nov. 22^nd, 2024 Dr. Timilehin Ogunbeku, Physics Division, Lawrence Livermore National Laboratory

   Leveraging the FDSi’s Complete Decay Spectroscopy Capabilities: the Structure of Neutron-rich ⁵⁴Sc

  Host: Dr. Ben Crider

  Instruction: In-person in Hilbun R-150

  Abstract:

       Advancing our understanding of shell evolution as nuclei become more neutron-rich is essential for improving the predictive power of nuclear models - a key focus of radioactive ion beam facilities like the Facility for Rare Isotope Beams (FRIB). In one of the first experiments at FRIB, a cocktail of neutron-rich nuclei near ⁵⁴Ca was delivered to the two distinct high-resolution and total-absorption focal planes of the FRIB Decay Station initiator (FDSi), enabling comprehensive decay spectroscopy of these exotic nuclei. I will present an overview of the unique capabilities of the FDSi and discuss new results relevant to further understanding the structure of neutron-rich 54Sc which is uniquely positioned just above the Z= 20 shell closure, and between the N= 32 and N= 34 subshell closures.

Nov. 15^th, 2024 Dr. Matthew Knight, Physics Department, U.S. Naval Academy

   The surprising value of comet morphology: using an ancient technique to learn about our solar system’s fossils

  Host: Dr. Donna Pierce

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Comets are compelling objects of study since they preserve information about the conditions present during our solar system’s formation. These “dirty snowballs” have remained frozen at large distances from the Sun, but become active via the sublimation of their ices when they pass through the inner solar system. This activity releases both dust and gas, obscuring the still frozen nucleus and preventing its direct study. A handful of space missions to comets have yielded great insight into the nature of individual nuclei, but such missions are too costly to investigate the population as a whole. Instead, we rely on remote observations using Earth-based telescopes.
       I will discuss how the study of comets’ morphology, particularly using specialized narrowband filters able to isolate specific gases, allows us to learn about their hidden nuclei. Although assessment of comet morphology has been occurring for centuries, recent advancements have resulted in huge leaps in what information can be gleaned from these observations. Furthermore, we are entering an exciting new era in which JWST and the Rubin Observatory will revolutionize our understanding of comets and related bodies; I will discuss how I am enabling more widespread use of narrowband imaging to complement these next generation facilities.

Nov. 8^th, 2024 Dr. Mahmoud M. Asmar, Physics Department, Kennesaw State University

   Vortex States and Magnetic Interactions in Light-driven Quantum Material

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       The discovery of Dirac and topological materials has opened new avenues for electronic and optoelectronic applications. Enabled by advancements in high-intensity, broadband radiation sources, Floquet engineering—a technique that drives systems beyond equilibrium through optical modulation—has gained momentum. This presentation will examine periodically driven two-dimensional Dirac materials, highlighting Floquet engineering’s impact on phenomena such as carrier-mediated magnetic (RKKY) interactions, light-induced topological and vortex states, and the emergence of higher-order topological insulators.

Nov. 1^st, 2024 Mr. Nathan Rutherford, Physics & Astronomy Department, University of New Hampshire

  Probing asymmetric dark matter admixed neutron stars with Bayesian inference and neutron star mass-radius measurements

  Host: Dr. Angelle Tanner

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Asymmetric dark matter (ADM) can accumulate in neutron star interiors and affect their global properties, such as their masses and radii. Considering the effects of ADM accumulation, neutron stars and their mass-radius measurements can not only be used to deliver new insights into the cold dense matter equation of state (EoS), but also be used as a hunting round for dark matter. In this talk, I will share how we employ Bayesian parameter estimation using current and future neutron star mass-radius data to infer constraints on the combined baryonic matter and ADM EoS, where the ADM is modeled as either a boson or fermion and forms a core in the neutron star interior. For the remainder of the talk, I will discuss the results that we have inferred from this Bayesian approach.

Oct. 25^th, 2024 Dr. Shao-kai Jian, Physics & Engineering Department, Tulane University

   Novel physics at the temporal boundary

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       Boundary physics plays a crucial role in various disciplines. I will talk about the physics of temporal boundaries created by weak measurements. Firstly, I discuss the effect of measurement and postselection on a Luttinger liquid theory. Depending on the Luttinger parameter K, measurement effects can be irrelevant, marginal, or relevant. When measurement is marginal, a critical state emerges with entanglement entropy exhibiting logarithmic behavior, characterized by a continuous effective central charge. Inspired by these findings, the second part delves into a holographic description of weak measurements. Here, we propose that weak measurement can be modeled by an interface brane, separating different geometries corresponding to the post-measurement and unmeasured states. The effect yields a diverse phase diagram of geometries.

Oct. 18^th, 2024 Dr. Heidrun Schmitzer, Physics & Engineering Department, Xavier University

   A Career in Physics

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       In this talk, Dr. Heidrun Schmitzer shares her personal journey and experiences in the field of physics. From her early inspirations and educational background to her current research and professional achievements, she will discuss the challenges and opportunities she encountered along the way. The presentation will highlight key moments in her career, including collaborations, discoveries, and her contributions to the broader scientific community. It aims to inspire young scientists and students by emphasizing the importance of curiosity, persistence, and teamwork in shaping a successful career in physics.

Oct. 11^th, 2024 Fall Break: No Colloquium; Enjoy :) and be Safe!

Oct. 4^th, 2024 Dr. Grigory Rogachev, Department of Physics & Astronomy, Texas A&M University

   Clustering in nuclei – the present state-of-the-art

  Host: Dr. Anatoli Afanasjev

  Instruction: In-person in Hilbun R-150

  Abstract:

       Multi-nucleon correlations or nuclear clusters play an important role in nuclei, often determining the level structure and nuclear reactions cross sections. A better understanding of clustering in nuclei is necessary not only from the fundamental nuclear theory perspective but also from the point of view of nuclear astrophysics. The α-particle-induced reactions, such as α-capture, (α,n) and (α,p) are essential in stellar nucleosynthesis and they are often dominated by α-cluster degrees of freedom in participating nuclei. We will review the experimental evidence for clusters in nuclei, discuss the modern experimental techniques applicable to study clustering and benchmark the theoretical predictions.

Sept. 27^th, 2024 Dr. Santanu Banerjee, Physics Department, Tougaloo College

   Revolutionizing our future: Novel Applications of Nanotechnology in Environmental and Biomedical fields

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       The size and shape dependent properties of materials, along with the order of magnitudes enhancement of quantum effects at the nanometer scale, provide a new armory of tools to combat pressing environmental and biomedical challenges. Consequently, the development and growth of Nanotechnology has created novel solutions to broad ranging problems in these fields. A subset of such applications, which are highly sensitive and selective, primarily utilizing modified gold nanomaterials, will be discussed in this seminar.
      Arsenic pollution in ground water is a grave threat, estimated to be affecting 150 million people globally. The current lab-based methods of ground water Arsenic detection are time consuming and expensive. As an alternative, we have developed a glutathione (GSH), dithiotreitol (DTT), and cysteine (Cys) modified gold-nanoparticle based colorimetric assay for detection of Arsenic at a detection limit well below the World Health Organization guidelines (10-50 ppb, based on location), and selectivity over other analytes. We have also developed a dynamic light scattering (DLS) based assay, with an excellent detection limit (100 ppt).
      Biological as well as bioterrorism threats through microbes such as Salmonella and E-coli constitutes an urgent need for quick and easy detection and destruction of such agents. Using the corresponding antibody (anti-Salmonella or anti-Ecoli) conjugated gold nanoparticles can readily and specifically identify the respective microbes, utilizing antibody-antigen recognition through observed colorimetric change. This colorimetric change occurs due to aggregation of nanoparticles on the surface of the bacteria, leading to size dependent change in optical properties of the nanomaterials. A similar antibody-antigen interaction can be used for detection of specific cancer cells at very low concentrations. Furthermore, photothermal therapy using infrared lasers (benign non-ionizing radiation) can be utilized for selective destruction of harmful microbes or cancer cells, without affecting normal cells. Applications to anti-microbial resistant (AMR) bacteria will also be discussed.
      In addition to focusing on the Nanotechnology applications, wider ranging physics related opportunities at Tougaloo College will be briefly addressed, including some appropriate for Mississippi State students.

Sept. 20^th, 2024 Dr. Konstantin Dorfman, School of Physics and Electronic Science, East China Normal University

   High precision spectroscopy in frequency, time, and spatial domains: quantum light, high harmonics, and metasurfaces

  Host: Dr. Gombojav Ariunbold

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       In the first part of the talk, we will discuss how new quantum phenomena in complex systems can be studied and controlled using advances in both quantum optics and nonlinear spectroscopy. In particular, I investigate how to probe, control, and image the spectral information of these complex systems using squeezed quantum state of light generated via four-wave mixing and reveal the material information, which is not accessible by conventional classical photonics tools. The biphoton technique allows to extend quantum spectroscopy of time domain by nonlocal wavelength- to time mapping.
       In the second part of the talk, we will discuss a novel method for monitoring electronic coherences using ultrafast spectroscopy. This method is based on the time-domain high-order harmonic spectroscopy where a coherent superpostion of the electronic states is first prepared by the strong optical laser pulse using a three-step mechanism introduced by Lewenstein and Corkum. The coherent dynamics can then be probed by the higher order harmonics generated by the delayed probe pulse. A semi-perturbative model based on the Liouville space superoperator approach is developed for the bookkeeping of the different orders of the nonlinear response for the high-order harmonic generation using multiple pulses. Coherence between bound electronic states is monitored in the harmonic spectra from both the first and the second order responses and investigate nonadiabatic dynamics of conical intersections and avoided crossings. The multidimensional version of the technique allows for selective elimination of inhomogeneous broadening which allows to extend the strong field techniques to large macromolecules and materials.
      In the last part of the talk, we will present the metasurfaces as a novel platform for optical spectroscopy. Relying on the local orientation of nanostructures, Pancharatnam–Berry (PB) metasurfaces are currently enabling a new generation of polarization sensitive optical devices. A systematical mesoscopic description of topological metasurfaces is developed, providing a deeper understanding of the physical mechanisms leading to the polarization-dependent breaking of translational symmetry in contrast with propagation phase effects. Our theoretical model, which allows clear understanding of PB phase is proven in an experimental measurement involving Mach-Zehnder interferometric setup. We further demonstrate that the reconstruction of a multidimensional nonlinear polarization response of a nanomaterial can be achieved in a single heterodyne measurement by active manipulation of the polarization states of incident light. Using multidimensional spectroscopy, we show the possibility to track both stationary and transient delocalized charge distributions via detecting plasmonic populations and coherences.

Sept. 13^th, 2024 Ms. Claire Geneser, Physics & Astronomy Department, Mississippi State University

   Gaussian Process Modeling for Mass Estimates of Exoplanets around Active Stars

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       Exoplanet candidates identified by the Transiting Exoplanet Survey Satellite (TESS) often require 50 or more follow-up observations before determining a mass measurement. This requires the use of specially designed echelle spectrographs from which we are able to retrieve precise radial velocity (PRV) measurements. The number of observations surges when measuring PRVs in the presence of strong stellar variability. This pertains to most observations of planets around adolescent or young K dwarf stars. Our candidate, TOI-2443 b, is a sub-Neptune mass planet with an orbital period of 15.669 days and a radius of 2.69 R_earth in orbit around a relatively adolescent star which exhibits stellar variability of nearly 15 m/s. The PRV time series is modeled with a Gaussian Process (GP) which fits the stellar activity as a function of wavelength for each spectrograph. Combining PRV measurements at visible and near-infrared wavelengths reduces the impact of star spots or other sources of stellar variability on the time series which can be misinterpreted as a planetary signal. In this presentation, we review preliminary results of TOI-2443 b and we demonstrate how the GP model is able to recover a planetary signal through a sea of stellar variability.

Sept. 6^th, 2024 Dr. Gautam Rupak, Physics & Astronomy Department, Mississippi State University

   Nuclear structure, reactions and quantum computers

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       Scattering experiments are fundamental to understanding the microscopic structure of quantum objects. Scattering is a real-time process. However, realistic quantum many-body calculations on classical computers are usually done with Monte Carlo simulations in imaginary times. These calculations also suffer from severe signal to noise ratio problem as the system size grows. An algorithm for the real-time calculation of inelastic processes, on a quantum computer is presented. We demonstrate the feasibility of the method with several proof of principle calculations involving quantum computing hardware.

Aug. 30^th, 2024 Dr. Daniel Tapia Takaki, Physics & Astronomy Department, The University of Kansas

   Photons at the Energy Frontier

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       The study of ultraperipheral nuclear collisions (UPCs) is breaking new grounds in fundamental physics. Although experiments at BNL RHIC and at the CERN LHC are not designed to exploit photon-induced interactions there is a plethora of recent results on UPCs in a wide variety of subjects: imaging the nucleus, studying fundamental electromagnetic and electroweak processes, probing the nuclear matter, and searches for physics beyond the Standard Model. In this talk, we will discuss a selection of recent UPC studies, as well as new directions in light of new theoretical and phenomenological studies, including novel applications of quantum mechanics.

Aug. 23^rd, 2024 Dr. Wenliang (Bill) Li$*$ and Dr. Jaspreet S. Randhawa$**$, Physics & Astronomy Department, Mississippi State University

   $*$ Probing Proton's Identity using the Future EIC

   $**$ Decoding X-ray Binaries using Exotic Beams

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

      $*$ Proton as a member of the baryon family, holds a baryon number (identity) of one. Unlike the structureless leptons, the baryons are constructed of quarks and gluons. We will dive into the mystery of who carries the identity (baryon number) for the proton with the help from the future Electron-Ion Collider.

      $**$ In X-ray binaries a neutron star accretes material from its companion. Nuclear burning of accreted material on the surface of a neutron star leads to type-I X-ray bursts, which provide ideal astrophysical laboratories to study the properties of neutron stars, and synthesis of elements in the explosive astrophysical environments. New observations from these explosive astronomical events are generating exciting new challenges for nuclear physics and force a rethinking of old paradigms. To decode observations from X-ray binaries, new nuclear data on very exotic nuclei is required, e.g., nuclear reaction rates or detailed nuclear structure/properties of exotic nuclei. Facility for Rare Isotope Beams (FRIB), a newly developed world’s leading radioactive ion beam facility, will provide an unprecedented access to the very exotic proton-rich and neutron-rich nuclei. In this talk, I will highlight the need for new nuclear physics data to decode observations from X-ray binaries and how FRIB is opening a new window to explore the most exotic nuclei on earth, to provide much-needed data to facilitate model-observation comparison.

2024-2025 Committee