Department of Physics & Astronomy "Colloquia and Seminars" Series

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

Fridays @ 3:00 PM

Apr. 19^th, 2024 Dr. Mohamed Laradji, Department of Physics & Materials Science, The University of Memphis

   Highly-Ordered Self-Assemblies of Nanoparticles Induced by Lipid Membranes

  Host: Dr. Prabhakar Pradhan

  Instruction: In-person in Hilbun R-150

  Abstract:

       Many advanced applications require specific assemblies of nanoparticles (NPs). Considerable efforts have thus been made to fabricate nanoassemblies with specific geometries. Although nanoassemblies can be achieved through top-down strategies such as lithography, laser ablation, sputtering, and thermal decomposition, bottom-up strategies, based on the spontaneous process of self-assembly, constitute attractive alternative approaches to fabricating nanoassemblies. Bottom-up strategies for NPs' self-assembly involve components such as copolymers, DNA or RNA, proteins, cellulose, and liquid crystals. This talk demonstrates that lipid membranes constitute an alternative medium for self-assembling NPs into ordered nanoclusters or superlattices. When NPs adhere to a lipid membrane, they induce deformations to the membrane curvature that may extend over length scales well beyond the size of the NPs. In turn, these deformations lead to effective interactions between the NPs that may be either attractive or repulsive. In this talk, I will present results based on extensive molecular dynamics simulations, in conjunction with free energy calculations, of an implicit-solvent model of membrane-mediated interactions between NPs with different geometries and their ensuing self-assembly. In particular, I will show that surface modification of spherical NPs into Janus NPs leads to their self-assembly into highly ordered nanoclusters, which depend on the number of NPs adhering to the vesicle. These nanoassemblies include three Platonic solids, namely tetrahedron, octahedron, and icosahedron. I will also show that combining geometric and chemical anisotropies further enhances the diversity of the nanoassemblies, with details controlled by both the number of NPs on the vesicle and their aspect ratio. When Janus NPs adhere to planar membranes, they self-assemble into a hexagonal lattice, with a melting behavior in accordance with the classical Kosterlitz-Thouless-Halperin-Nelson-Young theory of two-dimensional melting. I will also show that the adhesion of spherical and spherocylindrical NPs onto the inner side of lipid vesicles leads to their self-assembly into ordered quasi-two-dimensional nanoclusters with aster and polygonal geometries.

Upcoming Colloquia/Seminars

Apr. 26^th, 2024 Dr. Rafayel Paremuzyan, Physics Division, Jefferson Lab

   Luminosity Upgrade of the CLAS12 Detector

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       Since the advent of the first particle accelerators, the needs of nuclear and particle physics have continually added new demands on particle accelerators and detectors. Over the past century, there has been a remarkable increase in the maximum achievable energies of particles, from a few hundred kilo electron volts to more than 10 tera electron volts. Additionally, significant advancements have been made in particle detectors, enhancing both detection accuracies and their ability to operate effectively under higher luminosities.
       In this colloquium, I will introduce the CLAS12 detector located in Hall-B at Jefferson Lab. Furthermore, I will discuss the ongoing efforts to upgrade the CLAS12 detector, enabling it to operate under higher luminosities.

Apr. 29^th, 2024 ***** End of the 2024 Spring Semester; Enjoy your Summer Break :)! *****

Past Colloquia/Seminars

Apr. 12^th, 2024 Dr. Maria Piarulli, Department of Physics, Washington University in St. Louis

   The importance of many-body nuclear effects in light nuclei

  Host: Dr. Dipangkar Dutta

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       A major goal of nuclear theory is to explain the wealth of data and peculiarities exhibited by nuclear systems in a fully microscopic approach. In such an approach, which we refer to as the basic model of nuclear theory, the nucleons interact with each other via many-body (primarily, two- and three-body) effective interactions, and with external electroweak probes via effective currents describing the coupling of these probes to individual nucleons and many-body clusters of them. These effective interactions and currents are the main inputs to ab-initio methods that are aimed at solving the many-body Schr¨odinger equation associated with the nuclear system under consideration. In this talk, I will discuss recent advances in Quantum Monte Carlo calculations of low-lying spectra and electroweak properties of light nuclei. Emphasis will be placed on the importance of many-body nuclear effects in nuclear systems.

Apr. 5^th, 2024 Dr. Paresh C. Ray, Department of Chemistry, Physics & Atmospheric Sciences, Jackson State University

   Bio conjugated Nanoarchitecture for Targeted Theranostic Application of Cancer, Multidrug resistance bacteria (MDRB) and SARS-CoV-2

  Host: Dr. Prabhakar Pradhan

  Instruction: In-person in Hilbun R-150

  Abstract:

      Due to the lack of early detection before metastasis and failure of current therapy to cure the disease, lung cancer contributes to the highest cancer-related mortality worldwide. Similarly, the rapid emergence of superbugs which are resistant to existing antibiotics is becoming a huge global threat to public health, which demands the discovery of next-generation antibacterial agents for combating superbugs. The emergence of Alpha, Beta, Gamma, Delta, and Omicron variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for several million deaths up to now. Herein, we will discuss our recent reports [1-6] on the design of bio-conjugated nanoarchitecture, which has the capability for theranostic applications of cancer, MDRB and SARS-CoV-2. Our reported data indicated nanomaterial-based surface spectroscopy can be used for targeted diagnosis of cancer, bacteria and viruses at very low concentration. Similarly, we will discuss how bio-conjugated nanoarchitecture can be used for theranostic applications.

[1] A. Pramanik et al., Bioconjugated Nanomaterial for Targeted Diagnosis of SARS-CoV-2, Acc. Mater. Res. 3(2), 134–148 (2022)
[2] A. Pramanik et al., Aptamer Conjugated Gold Nanostar-Based Distance-Dependent Nanoparticle Surface Energy Transfer Spectroscopy for Ultrasensitive Detection and Inactivation of Corona Virus, J. Phys. Chem. Lett. 12(8), 2166–2171 (2021)
[3] A. Pramanik et al., Water Triggered Synthesis of Highly Stable and Biocompatible 1D Nanowire, 2D Nanoplatelet, and 3D Nanocube CsPbBr3 Perovskites for Multicolor Two-Photon Cell Imaging, JACS Au 1(1), 53–65 (2021)
[4] A. Pramanik et al., Human ACE2 Peptide-Attached Plasmonic-Magnetic Heterostructure for Magnetic Separation, Surface Enhanced Raman Spectroscopy Identification, and Inhibition of Different Variants of SARS-CoV-2 Infections, ACS Applied Biomaterials 5, 4454-4464 (2022)
[5] A. Pramanik et al., Multi-Color-Emissive Magneto-Luminescent Nanoarchitectures for Targeted Identification of Heterogeneous Exosomes Associated with Lung Cancer Metastasis, ACS Appl. Bio Mater. 6, 6, 2446–2458 (2023)
[6] A. Pramanik et al., WO3 Nanowire-Attached Reduced Graphene Oxide-Based 1D–2D Heterostructures for Near-Infrared Light-Driven Synergistic Photocatalytic and Photothermal Inactivation of Multidrug-Resistant Superbugs, ACS Appl. Bio Mater. 6(2), 919–931 (2023)

Apr. 1^st, 2024$☆$ Dr. Michael Nycz, Department of Physics, University of Virginia

   Exploring the Nature of Matter: An Overview of Current and Future Experiments at Jefferson Lab and the EIC

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-250

  Abstract:

       The ongoing nuclear physics program at Jefferson Lab has been instrumental in advancing our understanding of the structure of the nucleus along with its constituent nucleons. In my talk, I will begin with a brief overview of electron scattering, followed by an outline of my current and future research program. This science program focuses on understanding the three-dimensional structure of the nucleon though semi-inclusive deep inelastic scattering, studying the two-photon effect (TPE) in deep inelastic scattering through transverse single spin asymmetries, and measuring the size of the TPE in elastic scattering. I will also discuss ongoing detector and hardware studies for the Solenoidal Large Intensity Device (SoLID), the new experimental apparatus planned to be constructed and installed in Jefferson Lab’s Hall A facility. Finally, I will briefly discuss growing efforts related to electroweak and Beyond the Standard Model (BSM) physics at the future Electron Ion Collider (EIC).

$☆$ Note the special day, time, and location: Monday @ 3:30 PM in R-250!

Mar. 29^th, 2024 Easter Break: No Colloquium; Enjoy :) and be Safe!

Mar. 22^nd, 2024 Dr. Sonny Mantry, Department of Physics & Astronomy, University of North Georgia

   Charged Lepton Flavor Violation

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       The discovery of neutrino flavor oscillations provided conclusive evidence of Lepton Flavor Violation (LFV) and the fact that neutrinos have mass. LFV in the neutrino sector is expected to induce lepton flavor violation in the charged lepton sector as well. However, the induced rates for such charged lepton flavor violating (CLFV) processes are exceedingly small, suppressed due to the smallness neutrino masses relative to the electroweak scale, and well beyond the reach of any current of planned experimental searches. As a result, any observation of CLFV will be an unambiguous signal of new physics, opening a window into possible new physics scenarios. In this talk, I will provide an overview of CLFV and the wide range of experimental searches, including the proposed Electron-Ion Collider (EIC).

Mar. 20^th, 2024$☆$ Dr. Hamza Atac Department of Physics, Temple University

   Generalized Polarizabilities of the Proton

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-250

  Abstract:

       The Generalized Polarizabilities are fundamental properties of the proton that characterize the system’s response to an external electromagnetic (EM) field. They describe how easily the charge and magnetization distributions inside the system are distorted by the EM field, mapping out the resulting deformation of the densities in the proton. As such, they reveal unique information regarding the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents together. Recent measurements of the proton GPs have challenged the theoretical predictions, particularly in regard to the electric polarizability. The magnetic GP, on the other hand, can provide valuable insight to the competing paramagnetic and diamagnetic contributions in the proton, but it is poorly known within the region where the interplay of these processes is very dynamic and rapidly changing. In this talk, recent results from the VCS-I experiment at JLab, the upcoming VCS-II experiment, as well as the potential to access the GPs with alternative experimental methods will be discussed.

$☆$ Note the special day, time, and location: Wednesday @ 3:30 PM in R-250!

Mar. 18^th, 2024$☆$ Dr. Ye Tian, Department of Physics, Syracuse University

   Exploring the Nucleon Structure via Electron Scattering Experiments at JLab

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-250

  Abstract:

       The vast majority of visible mass is concentrated in atomic nuclei consisting of nucleons (protons and neutrons), which are composed of quarks and gluons. Although the strong interaction between these constituents is described by the theory of quantum chromodynamics (QCD), our understanding of the structure of nuclei and nucleons is still far from complete. Electron scattering, as a unique probe revealing the internal structure of nucleons, allows to access different Q$2$ regimes through the virtual photon exchange, which is crucial in understanding the internal dynamics of the strong interaction in the non-perturbative regime. In this talk, I will discuss my proposed research program in exploring nucleon properties such as electroexcitations of nucleon resonances on neutrons, the three-dimensional imaging of the nucleon in momentum space, and the neutron spin structure function g$$₂ⁿ via electron scattering experiments at the Thomas Jefferson National Accelerator Facility (JLab).

$☆$ Note the special day, time, and location: Monday @ 3:30 PM in R-250!

Mar. 15^th, 2024 Spring Break: No Colloquium; Enjoy :) and be Safe!

Mar. 8^th, 2024 Dr. Martha Constantinou, Department of Physics, Temple University

   Synergy of High-Performance Computing and Nuclear Physics to resolve long-standing puzzles: the proton spin and mass decompositions

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       More than 99% of the mass of the visible matter resides in hadrons, which are bound states of quarks and gluons, collectively called partons. These are the fundamental constituents of Quantum Chromodynamics (QCD), the theory of strong interactions. Understanding hadron structure in terms of the constituent quark and gluons is among the frontiers of Nuclear and Particle Physics. The 2015 Nuclear Science Advisory Committee’s Long Range Plan for Nuclear Physics identifying a future US-based electron-ion collider (EIC) as the highest priority for new facility construction. In 2019, the National Academies of Sciences, Engineering, and Medicine (NAS) released an assessment report that strongly endorses the EIC science, and last year, the EIC has been approved by the DoE. The NAS report identified three high-priority science questions to understand the hadron structure:
1. How does the mass of the nucleon arise?
2. How does the spin of the nucleon arise?
3. What are the emergent properties of dense systems of gluons?
      The above questions are among the long-standing puzzles of Nuclear Physics, and progress in theory is equally important as the experimental efforts. While QCD is an exquisite theory, it is highly non-linear and cannot be solved analytically. This poses severe limitations on our knowledge of the hadrons' structure. Lattice QCD is a powerful first-principle formulation that enables the study of hadrons numerically, which is done by defining the continuous equations on a discrete Euclidean four-dimensional lattice. The numerical simulations require large high-performance computing resources, and therefore, progress in lattice QCD cannot be achieved without access to supercomputing centers, state-of-the-art computer architecture, and improved algorithms.
      In this talk, I will discuss recent development in Lattice QCD related to aspects of the questions that the EIC will address, with the main focus being on the origin of the mass and the spin decomposition. I will show results for the proton, which provides an ideal system for studying QCD dynamics. I will discuss the strengths of lattice calculations and identify the challenges associated with eliminating systematic uncertainties.

Mar. 6^th, 2024$☆$ Dr. Wenliang (Bill) Li, Center for Frontiers in Nuclear Science, Department of Physics, Stony Brook University

   Identity of the Proton

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-250

  Abstract:

       Proton as a member of the baryon family, holds a baryon number (identity) of 1. Unlike the structureless leptons, the baryons are constructed of quarks and gluons. In this colloquium, we will dive into the mystery of who carries the identity (baryon number) for the proton: quarks? gluons? or both?

$☆$ Note the special day, time, and location: Wednesday @ 3:30 PM in R-250!

Mar. 1^st, 2024 Mr. Muhammad "Farouk" Yusf$*$ and Mr. Erik Wrightson$**$ , Department of Physics & Astronomy, Mississippi State University

   $*$ Variational Quantum EigenSolver for a particle in a simple harmonic oscillator trap

   $**$ X17 and the Potential for Understanding Hidden Sector Particles at Jefferson Lab

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

$$

      $*$ We explore the paradigm shift in quantum computing and quantum information science, emphasizing the synergy between hardware advancements and algorithm development. Only now have the recent advances in quantum computing hardware, despite a century of quantum mechanics, unveiled untapped potential, requiring innovative algorithms for full utilization. The project at hand utilizes Variational Quantum Eigensolver (VQE) to address the difficulties in adiabatic quantum computations, highlighting Singular Value Decomposition (SVD) in quantum computing. Results demonstrate an accurate ground state wavefunction match with only < 0.1% error in the energy. This work showcases quantum computing’s transformative potential in computational science.​

      $**$ The Standard Model (SM) is one of the most successful and extensive theories in all of Physics. However, even with its obvious successes, there are clear shortcomings that have only become more in need of addressing as the years pass on. The largest issue of note is the fact that the SM only accounts for ~5% of all of the “stuff” in the universe. Observations of the effects of dark matter/dark energy mean that we need to look beyond the SM to see what may come next. A potential vector of interest for these theories reared its head in the results of the 2016 experiment from the ATOMKI collaboration out of Hungary when measuring the deexcitation of the Beryllium-8 nucleus. These have now been further supported by observations in the Helium-4 and Carbon-12 nuclei by the same group along with confirmations from a related group in Vietnam. These measurements along with observations from across the field of nuclear and particle physics like the muon g-2 anomalous magnetic dipole moment and a few others to be discussed lend credence to the idea of the existence of a ~17 MeV particle dubbed X17. The existence of an X17 particle produced via a small coupling to SM matter would potentially provide an explanation for many of these issues that have arisen over the last few years. As more and more groups find themselves looking for physics from the “hidden” sector, Jefferson Lab and the PRAD collaboration in Hall-B have specific capabilities that make it a good candidate for the search. Our magnet-less experimental setup along with our ability for high precision energy measurements means that our approved experiment (E12-21-003) is in a good space to see an X17 particle should it exist. Any findings here will be useful for confirming X17’s existence or narrowing search regions and further constraining what may be true of these potential hidden sector interactions.

Feb. 23^rd, 2024 Dr. Kerstin Nordstrom, Department of Physics, Mount Holyoke College

   How do you know if it will flow? Jamming and clogging of granular materials

  Host: Dr. Dipangkar Dutta

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Granular materials are not particularly exotic, but their strange mechanical behavior is not well-understood. Sand piles can support our weight, but the same sand flows smoothly through an hourglass. I will review some open questions in the granular materials community, and common methods to experimentally analyze their behavior. I will then present specific work in our lab on the phenomena of silo flow and clogging. We have 1) characterized the basic system with microstructural measurements of grain motion, 2) modified this system to include obstacles, and 3) varied gravity. In addition to fundamental interest, modifications 2) and 3) have potential connections to traffic/pedestrian flow and planetary/asteroid exploration respectively.

Feb. 16^th, 2024 Dr. Michelle Kuchera, Physics jointly with Mathematics and Computer Science Department, Davidson College

   Machine Learning applications in Nuclear and Particle Physics

  Host: Dr. Ben Crider

  Instruction: In-person in Hilbun R-150

  Abstract:

       Machine learning has become ubiquitous in data-rich applications. Fundamental physics research provides an exciting realm for machine learning research with applications ranging from experimental data acquisition through making theoretical predictions. This talk will introduce machine learning theory, highlighting applications from my group in nuclear and particle physics research. Specifically, I will focus on experimental applications for detector systems at the Facility for Rare Isotope Beams and CERN. I will highlight innovative approaches in machine learning that show promise in these physics applications.

Feb. 9^th, 2024 Dr. Noel Richardson, Physics & Astronomy Department, Embry–Riddle Aeronautical University

  Constraining massive binary evolution through individual system studies

  Host: Dr. Angelle Tanner

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Massive stars are almost always found in binary or higher order systems. The result of this high multiplicity is that standard, single-star evolutionary models are not able to accurately predict the populations that exist in the massive star zoo. In order to understand how these stars ionize their environments, enrich the interstellar medium with gas and dust, or to piece together the diversity of supernovae, we need to understand binary star evolution in the upper H-R diagram. In this talk, I will describe observational campaigns on a variety of massive (and exotic!) Galactic binaries that will start to constrain the evolutionary pathways these stars can take compared to the standard single-star models.

Feb. 2^nd, 2024 Dr. Sylvester J. Joosten, Physics Division, Argonne National Laboratory

   Unveiling the Mass Structure of the Proton through Electron-Scattering Experiment

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       The proton, a key building block of all visible matter, boasts intrinsic properties such as electric charge, mass, and spin. These features are born from the intricate dynamics of its fundamental constituents - quarks and gluons. While the electric charge and spin of protons have been extensively studied via electron scattering, leading to substantial knowledge of the proton’s electric charge radius, our comprehension of its mass structure, predominantly governed by the energy of the gluons, is still limited. This colloquium will explore the process of studying the proton’s mass structure with photoproduction and electron scattering experiments, drawing parallels with the measurement techniques of the neutron skin in lead-208. I will discuss our most recent findings on the proton’s mass radius, achieved through near-threshold J/ψ photoproduction at Jefferson Lab. Lastly, we will outline future experiments at Jefferson Lab and the Electron-Ion Collider aimed at further elucidating the mass structure of nucleons and nuclei.

Jan. 26^th, 2024 Dr. Leah J. Broussard, Physics Division, Oak Ridge National Laboratory

  Understanding the beta-decay and other strange disappearances of the neutron

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       The neutron's transformation into a proton, electron, and antineutrino—a process called beta decay—should be well described by the Standard Model of Particle Physics. Precision measurements of observables in beta decay provide a robust and comprehensive test of our understanding of the electroweak interaction. However, experimental results are currently in significant tension with predictions. The Nab experiment, now commissioning at the Spallation Neutron Source, will perform the world's best determination of the correlation between the electron and antineutrino in neutron beta decay. This correlation, along with the neutron beta-decay lifetime, is used in one of the most precise tests of the semi-leptonic weak interaction, the unitarity test of the quark-mixing Cabibbo Kobayashi Maskawa matrix. In this colloquium, I will describe how Nab's novel approach will both improve precision of this test and shed light on experimental discrepancies. I will also discuss recent and planned searches for exotic transformations of the neutron, proposed to explain discrepancies such as in neutron lifetime measurements, and the potential implications for our understanding of how matter evolved in the universe.

Jan. 19^th, 2024 Dr. Lamiaa El Fassi, Physics & Astronomy Department, Mississippi State University

   Chasing QCD signatures in atomic nuclei: How do we shrink the "rho" meson?

  Host: Dr. Jeff Winger

  Instruction: In-person in Hilbun R-150

  Abstract:

       Over the last few decades, several experiments have used atomic nuclei as unique laboratories to probe the internal structure of the strongly interacting particles, namely hadrons. Indeed, the nucleus can be used as a revealing medium of the time evolution of elementary configurations of the hadron wave function. One of the ordinary approaches to probing this picture involves searching for the onset of various phenomena naturally predicted by quantum chromodynamics (QCD), the theory of strong interactions. One such phenomenon is color transparency (CT), which refers to the production and propagation of small-size hadron-like configurations that, under certain circumstances, stay intact in their nuclear medium journey. In this talk, I will review the status of the experimental search for CT covering experiments spanning over decades. I will also highlight the 12 GeV CT experiments that have been either completed or ongoing at Jefferson Lab.

       This work is supported in part by the U.S. DOE contract # DE-FG02-07ER41528.

2023 Fall Colloquia/Seminars Series

Dec. 1^st, 2023 ***** End of the 2023 Fall Semester; Enjoy your Winter Break & See you in 2024 Bright, Happy, and Shine :)! *****

Nov. 28^th, 2023$☆$ Mr. Nic Ezzel, Department of Physics, University of Southern California

   What’s going on in quantum computing these days?

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       ​In the first half of the talk, I provide a bird’s eye view of current quantum computing research from the perspective of a graduate student. My goal is to survey popular ideas circulating in the field at a high level but with enough care to convey (seemingly) important outstanding problems. In the second half, I discuss some of my own research in a bit more detail. Here I hope to convey different possible approaches to contributing to a quantum computing research project.

$☆$Note the special day and time, Tuesday @ 4 PM!

Nov. 24^th, 2023 ***** Happy & Safe Thanksgiving Break! *****

Nov. 17^th, 2023 Dr. Arun Paramekanti, Department of Physics, The University of Toronto

   Sleuthing spins

  Host: Dr. Dipangkar Dutta

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       ​Refrigerator magnets reflect the simplest form of magnetism in solids. The sleuthing of more complex forms of magnetism has necessitated the use of new concepts as well as new theoretical and experimental methods. In this talk, I will highlight a few examples of such systems ranging from topological magnets to multipolar magnets to quantum spin liquids.

Nov. 10^th, 2022 Dr. Deniz Yavuz, Department of Physics, University of Wisconsin–Madison

   Collective Spontaneous Emission in Ultracold Atomic Ensembles

  Host: Dr. Gombojav Ariunbold

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Since the pioneering work of Dicke almost 70 years ago, collective (cooperative) spontaneous emission has remained an active research area, continually finding new applications, most recently in areas related to quantum information science. I will discuss our recent experimental and theoretical work where we study collective spontaneous emission from ultracold, laser-cooled ensembles, in a mesoscopic regime, with atom numbers ranging from about one hundred to about one million. A unique aspect of our work is that we study collective decay in dilute ensembles (very few atoms per cubic wavelength of volume) that have a very low optical depth, and in the strong excitation regime (a large fraction of the atoms in the ensemble are excited). I will discuss several unique effects that can be observed in these systems such as superradiance-to-subradiance transition and the spatial coherence of the spontaneously emitted light. I will also discuss the connection of our results to various related research areas including fault-tolerant quantum computation.

Nov. 3^rd, 2023 Dr. Manoj Kaplinghat , Department of Physics & Astronomy, University of California, Irvine

   Searching for a Dark Sector

  Host: Dr. Dipangkar Dutta

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       ​Dark matter is inferred to be the dominant form of matter in the universe. After a brief summary of these inferences, this talk will motivate the idea of a dark sector of particles and laboratory searches for it. Dark sector particles will interact via new force(s), which can leave its imprint on galaxies, and these imprints could be uncovered through observations of gravitational lensing.

Oct. 27^th, 2023 Dr. Alexander Volya, Department of Physics, Florida State University

   Nuclear Physics Near Decay Thresholds

  Host: Dr. Anatoli Afanasjev

  Instruction: In-person in Hilbun R-150

  Abstract:

       ​The interaction between the quantum many-body system and the continuum of reaction states has a significant impact on its dynamics, especially near the decay threshold. This interaction causes changes in the wave functions with respect to the decay channels, resulting in phenomena such as threshold discontinuities, collectivization of states, clusterization, symmetry breaking, and interplay between decay and internal dynamics.
      This presentation will highlight recent advancements in theory and experimental studies related to the threshold physics in atomic nuclei. We will delve into topics such as alpha clustering close to decay thresholds, isobaric mirror resonant reactions that demonstrate the importance of coupling to the continuum, and the unique case of 11Be decay. Additionally, the recent research on few-body decays, both direct and sequential, as well as dynamics involving virtual excitations will be highlighted.

Oct. 20^th, 2022 Dr. Yuri Rostovtsev, Department of Physics & Center for Nonlinear Sciences, University of North Texas

   Quantum Coherence in various Materials: Transparency, Harmonic Generation, Quantum Correlations, and Masers at Room Temperature

  Host: Dr. Gombojav Ariunbold

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Spectroscopy of materials can be enhanced by the quantum coherent effects. It is the quantum coherence effects such as electromagnetically induced transparency and coherent population trapping that attract attention due to the increasing development of new applications such as high-precision spectroscopy, and large Kerr nonlinearities. Localized plasmon interaction in quantum confined structures strongly modify the optical and electronic properties with potential for manipulating light on the nanoscale. Another approach to demonstrate quantum coherent and cooperative effects is to study the Bi-exponential decay of dye fluorescence near the surface of plasmonic metamaterials and core-shell nanoparticles that has been shown to be an intrinsic property of the coupled system.
      We have demonstrated the new sensing mechanism based on an adiabatically changing electric field interacting with the rotational structure of the molecules with dipole moments. We have theoretically demonstrated a single low frequency gas detector that can be used for sensing of gas mixtures with high selectivity, accuracy, and sensitivity. The enhancement of the population difference between corresponding molecular levels and reached the theoretical maximum of absorption have been shown. Such a gas sensor can be used for a huge range of applications -- stretching from technology, sciences, control of environment, biology and medicine.

Oct. 13^th, 2023 Fall Break: No Colloquium; Enjoy :) and be Safe!

Oct. 6^th, 2023 Dr. Vinh Nguyen Du Le, Department of Physics & Astronomy, The University of Alabama in Huntsville

   Advanced Diffuse Optical Spectroscopy (DOS) for Continuous Monitor of Cerebral Blood Flow (CBF) and Heart Rate (HR)

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       CBF and HR are biomarkers for Traumatic Brain Injuries (TBI) and Obesity, respectively. In the U.S., there are nearly 70,000 TBI-related deaths and 300,000 obesity-related deaths each year and their combined health care cost exceeds $200 billion/year. Continuous and accurate measuring of CBF and HR can detect TBI early and better monitor obesity, thus improving the disease's prognosis. However, there is no accepted way to monitor CBF continuously and non-invasively in critically ill patients. Current clinical practice relies on snapshots of CBF and/or inferring CBF through surrogate indices. Meanwhile, recent studies have indicated that healthcare innovation inequalities may exist among optical wearable devices, resulting in inaccurate HR measurements in people with darker skin tone and thicker skin. In this talk, I will introduce advances in DOS that my research laboratory at UAH is developing to address these issues.

Sept. 29^th, 2022 Dr. Raghav K. Elayava, Department of Physics, Vanderbilt University

  Back to fundamental QCD - how do quarks and gluons evolve in space and time?

  Host: Dr. Dipangkar Dutta

  Instruction: In-person in Hilbun R-150

  Abstract:

       Collider experiments have proven themselves immensely useful in studying the behavior of fundamental particles such as quarks and gluons. The last few years, in particular, have seen a push towards an exploration of QCD, that has hitherto been inaccessible, via innovative experimental techniques to access the multi-scale parton evolution and eventually even shed light on hadronization mechanisms. In this talk, I start with a pedagogical overview of jets and their structure and highlight recent measurements from experiments at both RHIC and LHC. In the context of heavy ion collisions, jets have been advertised for the past two decades as a useful tool for quark-gluon plasma (QGP) tomography. This quest has had its fair share of roadblocks but I share the community's roadmap to the next generation of measurements with the sPHENIX detector at RHIC, that have untapped potential to extract the QGP's microscopic transport properties and in mapping its space-time evolution. Finally, I cover the impact of the upcoming Electron Ion Collider where these novel techniques and experimental precision lead to imaging both the perturbative and non-perturbative QCD regimes, allowing us unprecedented access to color confinement and hadronization.

Sept. 22^nd, 2023 Dr. Bryson Cale, Jet Propulsion Laboratory, California Institute of Technology

   Retrieval and Applications of Precise Radial Velocities to Detect Exoplanets

  Host: Dr. Angelle Tanner

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Radial Velocity (RV) measurements are crucial to independently confirm the existence of and characterize extrasolar planets and is the most successful means by which to infer an exoplanet's mass and bulk composition. In this talk, I will first provide a brief history and current status of the search for exoplanets, and the primary challenges astronomers face in the quest for an Earth analogue. I will describe the algorithms to accurately measure the relative velocities of stars from high resolution echelle spectra collected from a variety of ground-based facilities and will conclude with a subset of noteworthy results.

Sept. 15^th, 2023 Dr. Natalie Hinkle, Department of Physics & Astronomy, University of Texas at San Antonio

   Stellar Abundances and Their Influence on Small Rocky Planets

  Host: Dr. Angelle Tanner

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       The future for exoplanet science is dependent not only on successful missions such as TESS, JWST, and Roman, but also on building bridges to the geology, planetary science, and data science communities. It is by using the resources and experiences from these other disciplines that we can uncover more subtle trends within exoplanetary data and establish a holistic connection between stars and planets. As part of my interdisciplinary research, I study the patterns in stellar abundances using the Hypatia Catalog, the largest elemental abundance dataset for stars near to the Sun. Because stars and planets are formed at the same time, meaningful connections can be made between the chemical properties of stars and their orbiting planets. I will discuss how stellar abundances may be used to determine the raw materials available during planet formation, which impact the surface composition, tectonic processes, and other planetary geochemical cycles which directly influence the overall habitability. I will also describe my work on M-dwarf stars, which are the most common stars in the galaxy and easiest for detecting rocky planets but are extremely difficult to observe and characterize.

Sept. 12^th, 2023$☆$ Dr. Udit Raha, Department of Physics, Indian Institute of Technology Guwahati

   Universality of two neutrons and one flavored meson in Pionless Effective Theory

  Host: Dr. Gautam Rupak

  Instruction: In-person in Hilbun R-150 ONLY

  Abstract:

       In this talk, I shall present our investigation of the s-wave three-body system of two neutrons and one flavored meson with total spin-isospin $J=\; 0,\; I=\; 3/2$. The meson-neutron scattering length can become infinitely large when extrapolated to an unphysical region of the quark mass between strangeness and charm in the so-called zero coupling limit. Using pionless EFT at the leading order, we demonstrate that the well-known Efimov effect is formally manifest in the three-body system when the meson-neutron scattering length approaches the unitary limit of the two-body interaction. I shall thereby discuss the consequence of remnant universal physics in the physical K$-nn$ and D$0nn$ systems. Our results are indicative of the fact that a ground state of the D^0nn system is much more likely to be realized as halo-bound state than for the K$-nn$ system under reasonable idealization of eliminating (subthreshold D$0n$) decay channels. To that end, certain qualitative estimations about the three-body character of such an ostensibly bound D$0nn$ system shall be discussed.

$☆$ Note the different date of this special nuclear physics colloquium, Tuesday!

Sept. 8^th, 2023 Dr. Luqi Yuan, Department of Physics & Astronomy, Shanghai Jiao Tong University

   Novel optical phenomena with synthetic frequency dimension

  Host: Dr. Gombojav Ariunbold

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Synthetic dimensions in photonics have been under rapid development and attract great interests in past few years. Different degrees of freedom of light can be utilized to construct the synthetic dimension. Here​, I will discuss the opportunity of constructing the synthetic frequency dimension in dynamically modulated ring resonator systems, where the connectivity of the artificial lattice structure can be designed in a synthetic space including the frequency axis of light. Hence​, interesting physics and novel optical phenomena, including the effective magnetic flux for photons, the flatband physics, the dynamic band structure, as well as the non-equilibrium topological dynamics, the topological invariant extraction can be studied with the synthetic frequency dimension. Our works may open up an interesting avenue for studying important optical physics in photonics with potential applications in fields of optical signal processing and quantum simulations.

Sept. 1^st, 2023 Dr. Xiaopeng Li, Department of Physics, Fudan University

   Computation with Atomic Quantum Simulations

  Host: Dr. Mark Novotny

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Atoms are natural qubits for their fundamental property of being identical, and the consequent convenience in achieving scalable quantum control of large number of qubits. Atomic quantum systems have been largely exploited for quantum simulations. This talk will present programmable quantum simulation schemes to solve difficult computation problems. I will first discuss how to use atomic quantum simulations to solve 3-SAT, vertex-cover, and binary optimization problems, considering Rydberg atoms and optical cavity systems. With Rydberg the encoding complexity for 3-SAT and vertex cover is quadratic, whereas the encoding complexity with optical cavity is linear. Secondly, I will describe using quantum simulations of many-body dynamics to construct quantum reservoir computing models. In its applications to FX-market forecast, we find it has remarkable prediction accuracy, beating the classical reservoir computing predictions. Our recent results imply atomic quantum simulations provide a promising route to search for practical quantum advantage.

Aug. 25^th, 2023 Dr. Abhay Deshpande, Department of Physics & Astronomy, Stony Brook University

   Electron-Ion Collider: — Science and journey to its realization

  Host: Dr. Lamiaa El Fassi

  Instruction: In-person in Hilbun R-150

  Abstract:

       Endorsement of the science case of the Electron-Ion Collider (EIC) in 2019 by the US National Academy of Sciences, Engineering and Medicine triggered the move by the US Department of Energy (DoE) in 2020 to initiate the EIC Project to realize the EIC. The three pillars of its science: the origin of proton’s mass, spin, and investigation of high gluon fields inside the nuclei at the highest energies — all centered around well known and somewhat embarrassing deficit in our understanding of the role of gluons in QCD — are the central goals of investigations of this future QCD machine. Due to its high luminosity coupled with variable energy & polarization of beams, aspects of beyond the Standard Model physics also come into its purview. The diversity of the physics program will offer a broad range of opportunities for nuclear to particle physicists. The versatility in operations demanded by the physics program makes the EIC one of the most challenging machine ever to be built, presenting exciting research opportunities for nuclear, particle, and also accelerator scientists. International collaborations are now being formed both on the detector and for the accelerator. The EIC is expected to start taking data in early 2030s.
      In this talk, I will review the science of EIC, and comment on the current activities of the project, including the theoretical development on refining the science case, detector design, planning, and the start of construction. I will also cover exciting opportunities for early career (students, postdoctoral fellows) and senior scientists to participate and make impactful contributions.

Aug. 18^th, 2023 Dr. Sonny Mantry, Department of Physics & Astronomy, University of North Georgia

   Jets as Standard Candles for Particle Physics at Colliders

  Host: Dr. Dipangkar Dutta

  Instruction: Virtual in ZOOM ONLY

  Abstract:

       Jets correspond to highly collimated sprays of energetic particles that emerge from high energy collisions using beams of electrons, protons, or heavier nuclei. Jets are an emergent phenomenon arising from the structure and dynamics of gauge theories such as Quantum Chromodynamics. They serve as beacons for hard interaction processes involving quarks, gluons, and the production of heavy resonances. In fact, the gluon was first discovered from a characteristic three-jet event signature. Understanding the structure, substructure, and dynamics of jets helps us unravel the structure of nucleons and nuclei, the interactions of elementary particles, and hints of new physics. In this talk, I will give a pedagogical introduction to the physics of jets and discuss some of their applications, including using jet-based global event shapes as a probe of nuclear structure and dynamics, probing quark flavor dynamics using the electric charge of jets, using jet discrimination techniques to enhance signal over background, and precision extractions of the top quark mass.

2023-2024 Committee