Events

Thomas Werfel
Department of Chemical Engineering
University of Mississippi

Targeted Therapies at the Interface of Nanotechnology and Cancer Biology

In the Interdisciplinary NanoBioSciences (iNBS) Lab, we work largely at the interface of nanotechnology and cancer biology. The complexity of cancer necessitates creative, multi-faceted solutions that nanotechnologies have the potential to offer. However, the successful application of nanotechnologies is currently stymied by oversimplified biological models and a dearth of data from advanced biological studies that faithfully recapitulate human disease. Ultimately, our scientific goals are to better understand nanomaterial-biological system interactions to improve the performance of nanotechnologies in humans, discover new cancer molecular targets ideal for nanotechnology-based therapies, and identify cellular and molecular processes that impact drug delivery efficiency, cancer metastasis, and resistance to therapy. In this colloquium, I will highlight three research thrusts in the iNBS Lab that span nanotechnology and targeted cancer therapy: 1) Drugging previously 'undruggable' cancer-causing genes with siRNA nanomedicines, 2) Combating the immunosuppressive impact of efferocytosis in the tumor microenvironment, and 3) Targeting the platelet-tumor cell interaction to prevent breast cancer metastasis.

Kyle Parfrey
Astrophysics Division
NASA Goddard Space Flight Center

The Magnetic Lives of Black Holes and Neutron Stars

The most extreme and surprising behaviors of black holes and neutron stars are driven by their surrounding plasmas and magnetic fields. Numerical simulations which capture basic physical processes like particle acceleration, magnetic reconnection, and magneto-rotational turbulence can yield insight into such disparate phenomena as black-hole jets and X-ray coronae, magnetar giant gamma-ray flares, and the spin limit of millisecond pulsars. I will focus on what simulations can teach us about the launching of relativistic jets in compact binary mergers, and will describe how a new technique for general-relativistic plasma kinetics will aid in understanding black holes' jets and particle acceleration, and in interpreting future observations with the Earth-spanning Event Horizon Telescope.

Shaon Ghosh
Department of Physics
University of Wisconsin — Milwaukee

Astrophysics with Synergy of Electromagnetic and Gravitational Wave Observations

About three and a half years ago, the direct detection and measurement of gravitational waves from a pair of coalescing black holes by the LIGO interferometers opened a new window for astrophysicists to look into the universe. Almost two years later, the discovery of gravitational wave from a binary neutron star system marked the beginning of the era of joint electromagnetic and gravitational wave astronomy. In this talk, I will present a brief history of this discovery and its importance in that context. I will then focus on the rich scientific results of the multi-messenger observation and finally, discuss how such joint observations can help us extract astrophysical information from some of the most extreme objects in the universe. Specifically, I will highlight how observations of neutron stars can help us understand how matter behaves in conditions that cannot be replicated in earth-based laboratories. The required information for such studies comes to us from various avenues of astrophysical observations. I will delineate the methods that we will be employing in combining these information to make robust inferences on the neutron star equation of state.

Stephen Taylor
Division of Physics, Mathematics and Astronomy
California Institute of Technology

Frontiers of Multi-Messenger Black-Hole Physics

The bounty of gravitational-wave observations from LIGO and Virgo has opened up a new window onto the warped Universe, as well as a pathway to addressing many of the contemporary challenges of fundamental physics. I will discuss how catalogs of stellar-mass compact object mergers can probe the unknown physical processes of binary stellar evolution, and how these systems can be harnessed as standard distance markers (calibrated entirely by fundamental physics) to map the expansion history of the cosmos. The next gravitational-wave frontier will be opened within 3-6 years by pulsar-timing arrays, which have unique access to black-holes at the billion to ten-billion solar mass scale. The accretionary dynamics of supermassive black-hole binaries should yield several tell-tale signatures observable in upcoming synoptic time-domain surveys, as well as gravitational-wave signatures measurable by pulsar timing. Additionally, pulsar-timing arrays are currently placing compelling constraints on modified gravity theories, cosmic strings, and ultralight scalar-field dark matter. I will review my work on these challenges, as well as in the exciting broader arena of gravitational-wave astrophysics, and describe my vision for the next decade of discovery.

David Nichols
Institute of Physics
University of Amsterdam

Gravitational Waves and Fundamental Properties of Matter and Spacetime

Gravitational waves from the mergers of ten binary black holes and one binary neutron star were detected in the first two observing runs by the Advanced LIGO and Virgo detectors. In this talk, I will discuss the eleven gravitational-wave detections and the electromagnetic observations that accompanied the neutron-star merger. These detections confirmed many of the predictions of general relativity, and they initiated the observational study of strongly curved, dynamical spacetimes and their highly luminous gravitational waves. One aspect of these high gravitational-wave luminosities that LIGO and Virgo will be able to measure is the gravitational-wave memory effect: a lasting change in the gravitational-wave strain produced by energy radiated in gravitational waves. I will describe how this effect is related to symmetries and conserved quantities of spacetime, how the memory effect can be measured with LIGO and Virgo, and how new types of memory effects have been recently predicted. I will conclude by discussing the plans for the next generation of gravitational-wave detectors after LIGO and Virgo and the scientific capabilities of these new detectors. These facilities could detect millions of black-hole and neutron-star mergers per year, and they can provide insights on a range of topics from the population of short gamma-ray bursts to the presence of dark matter around black holes.

Sarah Vigeland
Department of Physics
University of Wisconsin — Milwaukee

Probing Massive and Supermassive Black Holes with Gravitational Waves

Observations have shown that nearly all galaxies harbor massive or supermassive black holes at their centers. Gravitational wave (GW) observations of these black holes will shed light on their growth and evolution, and the merger histories of galaxies. Massive and supermassive black holes are also ideal laboratories for studying strong-field gravity. Pulsar timing arrays (PTAs) are sensitive to GWs with frequencies ~1-100 nHz, and can detect GWs emitted by supermassive black hole binaries, which form when two galaxies merge. The Laser Interferometer Space Antenna (LISA) is a planned space-based GW detector that will be sensitive to GWs ~1-100 mHz, and it will see a variety of sources, including merging massive black hole binaries and extreme mass-ratio inspires (EMRIs), which consist of a small compact object falling into a massive black hole. I will discuss source modeling and detection techniques for LISA and PTAs, as well as present limits on nanohertz GWs from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration.

Anuradha Gupta
Department of Physics
Pennsylvania State University

Physics and Astrophysics with Gravitational Waves from Compact Binary Coalescences

The recent detections of gravitational waves from several binary black holes and binary neutron star mergers have opened up new avenues for gravitational wave astronomy and astrophysics. These detections provide us with great opportunities to study astrophysical sources in both weak and strong gravity regimes. In this presentation, I'll tell you how one does physics and astrophysics with gravitational waves emitted from compact binary coalescences. In particular, how to constrain binary formation mechanisms from their observed properties, how to test general relativity and other theories of gravity and lastly how to do precision cosmology with gravitational waves. I'll also touch upon the future prospects of these efforts.

Libo Jiang
Department of Physics & Astronomy
University of Pittsburgh

MicroBooNE - Using Neutrinos to Probe Nuclear Physics for the Future

MicroBooNE is a large 170-ton liquid-argon-Time Projection Chamber Neutrino experiment located on the Booster neutrino beamline at Fermilab. The detector serves as a next step in a phased program towards the construction of massive kiloton scale LArTPC detectors for future long-baseline neutrino physics (DUNE) and is the first detector in the short-baseline neutrino program at Fermilab. A major physics goals of the experiment is to probe the source of the anomalous excess of electron-like events in MiniBooNE/LSND with improved detection capabilities. In addition, MicroBooNE has an extensive cross section physics program that will improve current models on neutrino-nucleus interactions, especially nuclear effects in argon, and decrease systematic errors in the oscillation program. This colloquium introduces the detector & performance of MicroBooNE and summarizes the status of MicroBooNE's neutrino cross section analyses.

Jonathan Eisch
Department of Physics & Astronomy
Iowa State University

Reviving the Poltergeist: Bringing Water-Based Neutrino Experiments into the Precision Era with Efficient Neutron Detection

Advances in water-based neutrino-detection technology are setting the stage for a new generation of detectors to answer questions about the nature of matter in the universe and to make our world a safer place. Leading the way in these new technologies is the Accelerator Neutrino Neutron Interaction Experiment (ANNIE) at Fermilab. ANNIE will revisit the use of neutron capturing salts, pioneered in the first experiment to detect the neutrino, to detect the number of neutrons produced in GeV-scale neutrino interactions. This measurement, the first on a neutrino beam, will help push future neutrino-oscillation experiments into the precision era by separating quasi-elastic charged-current interactions from more complicated many-body neutrino interactions and thus improving the models of neutron production in neutrino interactions. The WATCHMAN experiment, under construction in the UK, will use the same technology at a much larger scale to demonstrate the ability to remotely monitor nuclear reactors from tens of kilometers away. This demonstration will enable remote reactor monitoring to be a part of future nuclear nonproliferation treaties. In this talk, I will describe the ANNIE and WATCHMAN experiments along with their impacts on detector technology development toward future large multipurpose neutrino detectors like Theia.

Gavin Davies
Department of Physics
Indiana University

The Wonderful World of Neutrino Oscillations

In 1998 it was discovered that neutrinos oscillate and have mass which led to the award of the 2015 Nobel Prize in Physics. That discovery generated a global campaign to better understand neutrino properties using oscillations of neutrinos produced in the Sun, in the atmosphere, at reactors, and by accelerators. The community has learned much but several important questions remain such as: Which neutrino is heaviest? Do neutrinos break the symmetry between matter and antimatter? Are there more than three neutrino types?

In my talk, I will introduce neutrinos and the questions surrounding them, their chameleon-like flavor-changing behavior, and the experiments that hunt for them including the leading-edge, international Deep Underground Neutrino Experiment.

Jingbo Wang
Department of Physics
University of California — Davis

Exploring the Neutrino Physics with the Deep Underground Neutrino Experiment

One of the biggest surprises in particle physics is that the neutrinos have mass, which was discovered by the neutrino oscillation experiments. This fundamental property of neutrinos leads to some new questions. What is the ordering of the neutrino mass states? Do the neutrinos violate the matter/antimatter symmetry? What characteristics does the neutrino mixing matrix have? The Deep Underground Neutrino Experiment (DUNE) will address these questions with the high-precision Liquid Argon Time Projection Chamber (LArTPC) technology. In this talk, I will give a brief overview of neutrino oscillations, then describe DUNE and its physics programs. I will also talk about the Pulsed Neutron Source as a newly proposed calibration technique for liquid argon TPCs. The precision measurements of the neutrinos will open a window to new physics beyond the standard model. The future and prospects will be discussed.

Xiaobo Chao
National Center for Computational Hydroscience and Engineering
University of Mississippi

Three Dimensional Numerical Modeling of Temperature Distribution in a High Dam Reservoir with the Effect of Channel Curvature on Mekong River

A three dimensional numerical model has been developed to simulate the flow circulation as well as temperature distribution in a high dam reservoir with the effect of channel curvature. In the model, the density induced buoyant force on the turbulent flow is considered. This “buoyancy-extended version of k-ε model” is used for turbulence closure, and the flow velocity and temperature distribution are simulated simultaneously. The model was first validated using a laboratory case of turbulent buoyant flow in a curved open channel. The secondary flow circulation in the curved channel was simulated and the temperature distribution in the channel was validated using experimental data. The model was then applied to simulate the flow and temperature distribution in Xiaowan Reservoir, a high dam reservoir on Mekong River, with deep water depth and curvature affect. The numerical results are generally in good agreement with field observations. The thermal stratification, temperature distribution in the reservoir and the effect of channel curvature on the temperature distribution are discussed.

Jason Fry
Department of Physics
University of Virginia

Precision Fundamental Symmetry Measurements With Cold Neutrons

The neutron can be used as a powerful tool to study a wide range of phenomena through many disciplines of physics. In particular, cold neutrons are utilized in condensed matter, nuclear, and particle physics with deep connections to cosmology. The free neutron has a slightly larger mass than the proton leading to far reaching implications. How long a free neutron lives determines how the light elements formed in the early universe. The kinematics of neutron decay give us insight into how quarks mix in the weak interaction. Additionally, as a neutral particle, neutrons can penetrate deeply into nucleons to further our understanding of how the strong and weak interaction mix at the smallest scales. In this talk, I will discuss the neutron physics experiments carried out and planned on the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source at Oak Ridge National Lab. The NPDGamma experiment, the first experiment on the FNPB, studied the most fundamental process in the Hadronic Weak Interaction (HWI) and the results set the best constraint for future investigation of the HWI. Currently we are commissioning the Nab experiment on FNPB which will make precise measurements of the electron neutrino correlation parameter "a" and the Fierz interference term "b" in unpolarized neutron beta decay. These results will lead to a new, precise, independent determination of the ratio λ = GA/GV that will sensitively test CKM unitarity.

Glenn M. Walker
Department of Electrical Engineering
University of Mississippi

Microfluidics: Thinking Small to Improve Biological Research

Microfluidics is the study of fluid behavior at micrometer length scales and the development of devices that leverage microscale fluid phenomena. A major focus of the field has been on solving problems in biology since biological cells typically range in size from 1–20 micrometers and are difficult to manipulate with traditional instruments. Researchers have been able to exploit the manipulation of fluid volumes down to the picoliter to enable biological experiments that were previously impossible. This talk will cover some of the microscale phenomena that become dominant at micrometer lengths and also show examples of enabling biological experiments. Research from our lab on high throughput screening and cancer cell hypoxia will also be presented.

Saeed Kamali
Department of Physics and Astronoimy
University of Mississippi

New Physics in Inclusive B → X_c τ ν_τ Decays in Light of R(D^*) Measurements

Kevin Lin
Department of Physics and Astronomy
University of Mississippi

Development of Vibrational Metrics for Internal Damage Scenarios of a Scaled Transnuclear-32 Dry Storage Cask for Spent Nuclear Fuel

The assessment of the internal structural integrity of dry storage casks for used high burnup nuclear fuel assemblies is of critical importance before transporting these to permanent repositories. The large size and structural complexity of the Transnuclear-32 (TN-32) cask as well as the inability to access its interior make this a challenging task. To address these difficulties, we use an active acoustics approach to develop metrics that are sensitive to the internal configuration of these casks. A 6:1 scaled model of the TN-32 cask was constructed in order to study internal configuration of the fuel assemblies including various damage scenarios. The vibration modes were verified in Finite Element simulations. Each mock-up fuel assembly consists of bundled steel rods, and their structural failure is mimicked by steel shot of equal weight. This talk will report the amplitude- and phase-based active acoustics metrics we developed to characterize different levels of internal damage. Our studies indicate that vibrometric signatures of various internal conditions can be measured using sources and sensors mounted on the exterior shell. Our current methodology is sensitive enough to detect structural failures at the single fuel assembly level.

Robert Lirette
Department of Physics and Astronomy
University of Mississippi

Droplet Extraction and Manipulation at a Fluid Interface Using Fraxicon Modified Ultrasound

Ultrasound focused at a fluid-fluid boundary creates an acoustic radiation pressure on the boundary that is dependent on the incident energy density and the relative density and sound speed of each fluid. For different fluid combinations this radiation pressure can either be positive or negative. For this study ultrasound propagating from water to carbon tetrachloride was used to create a negative radiation pressure at the interface. This fluid combination is impedance matched eliminating reflections and heating effects at the boundary. A fraxicon phase plate lens is a low profile analog of an axicon and generates an approximate Bessel beam in the far field. The near field exhibits a complex diffraction pattern including shadow zones capable of acoustic trapping. Starting with a planar interface, we demonstrate the extraction, capture, and manipulation of a carbon tetrachloride droplet. The negative radiation pressure draws the carbon tetrachloride surface up into the water, eventually breaking a droplet free. The trapped droplet is then transported through the water by moving the transducer.

Roger Waxler
Department of Physics and Astronomy
University of Mississippi

Infrasound Generation and Propagation in the Earth's Atmosphere

The term infrasound is applied to low frequency sound in the atmosphere, generally below the limit of human hearing. The frequencies of interest in our research range from 10 Hz down to as low as 0.001 Hz, corresponding to periods of 0.1 to 1000 seconds. Such signals tend to be geophysical in nature, propagating globally and generated by large, violent events such as hurricanes, tornadoes, earthquakes and large detonations. Their propagation depends critically on large scale temperature and wind velocity gradients. These produce a variety of acoustic ducts in the atmosphere. These are asymmetric with respect to azimuth and interact with each other. They are also spatially and temporally varying, with small scale fluctuations on top of diurnal and seasonal cycles. An overview of sources, generation and propagation of infrasound in the atmosphere will be presented.

Bhubanjyoti Bhattacharya
Department of Natural Sciences
Lawrence Technological University

CP Violation in the Precision Era

Anomalies in recent data present strong hints of physics beyond the Standard Model. Several new physics models, among them vector bosons and leptoquarks, have proven to be viable candidates in light of the data. Intensity frontier experiments will soon test many of these models through precision measurements of low-energy observables. In this talk I will present a subset of recent measurements that come with a hint of new physics. I will present proposals for testing and distinguishing between some of the popular new physics models, by using CP violating observables.

Department Students
Department of Physics and Astronomy
University of Mississippi

Reports on Summer Research

Carl Jensen
Transducer Technology Group
Bose Corporation

Sound Reproduction and Loudspeaker Structural Modes

Many familiar sources of sound involve vibrating structures like a piano sound board, an acoustic guitar's body, drums, and all kinds of vibrating machinery. Similarly, almost all technologies for mechanically producing sound also work by exciting some kind of vibrating structure as well, but, in sound reproduction, the goal is to recreate the original recording as accurately as possible. So the fact that all vibrating structures exhibit modal behavior can be good or bad: the diversity and excitation of modes in musical instruments lends them their unique sonic qualities and richness, but these same characteristics are very much unwanted in a loudspeaker meant for accurate reproduction. In this presentation, I'll discuss some of the principles of sound reproduction and perception as well as laying out how we can use computer simulations to untangle the complex acoustic behavior of these modes to understand their behavior and make better sounding loudspeakers.

Michel Villanueva
Department of Physics and Astronomy
University of Mississippi

Searches of New Physics with the Belle II Experiment

Despite the large success shown by the Standard Model of Elementary Particles describing subatomic processes, there are still many open questions in nature that cannot be explained by the Standard Model. Solving the issues faced by the Standard Model requires the introduction of new particles or interactions, which, if they exist, can be observed as deviations from the predictions of suppressed or forbidden processes. The Belle II experiment will play a critical role in searches for new physics at the "intensity frontier". First collisions took place in 2018 at the new SuperKEKB accelerator, which is expected to operate for the next decade, collecting 50 times more data than the previous generation of experiments of this kind. In this talk, the data production and physics programs of the Belle II experiment are presented, in which the High Energy Physics group of the University of Mississippi contributes to key roles. Of particular interest in my research are decays of the tau lepton, which provide a clean environment to the study of QCD related processes.

Tomas Galvez
Department of Physics and Astronomy
University of Mississippi

Quantum Cosmology and Sound Waves in the Early Universe

In this talk, we will review some of the conundrums of standard big bang cosmology and a few proposals designed to circumvent them. To do so, we study the quantum origin of perturbations in a perfect (or imperfect) fluid and show some useful techniques to calculate their corresponding two-point correlators. Our objective is to improve the accuracy and efficiency of the existing methods to evaluate primordial power spectra of scalar and tensor fluctuations, and therefore provide solid observational constraints. Our approach is to rewrite all the relevant equations of motion in terms of slowly varying quantities, which is important to consider the contribution from high-frequency modes to the spectrum without affecting computational performance. We do not require additional approximations to reproduce all the features in the power spectrum for each specific early universe model.

Department Students
Department of Physics and Astronomy
University of Mississippi

Reports on Summer Research

David Craig
Department of Chemistry and Physics
West Texas A&M University

From Astronomy to Acoustics and Back Again Through Undergraduate Research

After earning my PhD in physical acoustics at Ole Miss and a number of years at institutions almost exclusively devoted to teaching, I returned to active research by joining a team of astrophysicists working on projects that emphasize undergraduate research in observational cosmology. I will discuss the ways undergraduates have been involved in cutting-edge research via this team approach and overview the science behind the projects.

Our emphasis has been on HI (21 cm) radio surveys of nearby galaxies. These include the completed ALFALFA blind survey of the nearby universe, and the current targeted Arecibo Pisces-Perseus Supercluster Survey (APPSS) which attempts to detect dark matter-driven infall of galaxies onto a nearby supercluster filament. I will include a discussion of the observing strategies and the planned use of the baryonic Tully-Fisher relation to separate the effects of cosmic expansion and local peculiar velocities using Bayesian statistical methods.

Department Students
Department of Physics and Astronomy
University of Mississippi

Reports on Summer Research

Logan S. Marcus
Office of the Deputy Assistant Secretary of Defense for Chemical and Biological Defense
ANSER, Inc.

Careers in Science Outside of Academia

There is generational change in the way that scientists must approach their careers after graduating. According to Science Magazine, “…for U.S. science and engineering Ph.D.s, private sector employment (42%) is now nearly on par with educational institutions (43%).” Graduating students must be prepared to enter a job market that includes opportunities beyond traditional academic careers. In this presentation, I will discuss some of the many options for careers in science that are outside of the traditional academic path. I will explore example careers, offer advice to students on how to prepare themselves for those careers, and discuss skills that the University can emphasize to equip graduates before they leave Ole Miss.

Annemarie Exarhos
Department of Physics
Lafayette College

A Path Toward Spin-Based Quantum Technologies — Creating, Controlling, and Characterizing Quantum Emission

Optically-active point defects in wide-bandgap semiconductors are the basis for rapidly expanding quantum technologies in nanoscale sensing and quantum information processing. Most research has focused on three-dimensional host materials such as diamond and silicon carbide, where quantum mechanical spin states can be optically addressed. In recent years, the two-dimensional van der Waals material hexagonal boron nitride (hBN) has emerged as a robust host for bright, stable, room-temperature quantum emitters (QEs). However, many questions persist regarding the chemical and electronic structure of the defects responsible for emission as well as the potential role of spin-related effects. Significantly complicating the identification of these QEs is the heterogeneity of optical and magnetic characteristics observed.

I will discuss work regarding our studies of the optical and magnetic properties of QEs in hBN films, characterized via confocal fluorescence microscopy. In particular, I will report on our recent observations of magnetic-field dependent emission in some QEs that, if able to be well-isolated and controlled, could enable the realization of spin-based quantum technologies using low-dimensional van der Waals heterostructures.

Dr. Stuart Loch
College of Sciences and Mathematics
Auburn University

Spectroscopy of Laboratory and Astrophysical Plasmas: Applications for Fusion Plasmas, Merging Neutron Stars, and Planetary Nebulae

Plasmas are hot, ionized gases and are often called the fourth state of matter. Plasmas make up most of the observable Universe and laboratory plasmas have a wide range of research applications. Diagnosing the properties of plasmas presents a particular challenge, due to their temperatures and in the case of astrophysical plasmas, the large distances to the objects. Plasma spectroscopy represents a non-invasive method of diagnosing important plasma properties such as temperatures, densities, and elemental compositions. An overview is given of three research projects, involving the use of quantum mechanics calculations for diagnosis of laboratory plasmas. The projects involve measuring wall erosion rates from fusion plasma experiments, investigating the spectral emission from elements made in neutron star mergers, and the confirmation of a new atomic process found in planetary nebulae.

Jake Bennett, Roger Waxler, and Gavin Davies
Department of Physics and Astronomy
University of Mississippi

Departmental Research

There will be a brief report on some of the fields of research by our department. It will consist of the following:
Jake Bennet: Belle II
Roger Waxler: Infrasound
Gavin Davies: NOνa/Dune