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Department of Physics and Astronomy


Colloquia

These lectures feature speakers from around the country and globe. Each colloquium lasts about an hour and gives you a deeper understanding of the types of physics and astronomy researching going on around the world. 

January 2018 - December 2018

December 6, 2018 

"Tools Made of Light - An Overview of the Ideas Behind the 2018 Physics Nobel Prize"

Prof. Yanwen Wu

4:15 pm - 5:15 pm

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Dr. Yanwen Wu, Assistant Professor
Department of Physics and Astronomy
University of South Carolina

The 2018 Nobel Prize in Physics celebrates the invention of two important tools in optics:  the optical tweezers and the chirped-pulse amplification (CPA) technique.  The prize is shared by three physicists:  Donna Strickland (CPA), Gerard Mourou (CPA), and Arthur Ashkin (optical tweezers).  I will give a brief history of the development of tools made of light and provide an overview of the physics behind these latest additions to the light toolbox and their amazingly broad applications in areas ranging from basic research to everyday life.
 

November 29, 2018

"Gravitational Quantum States of Neutrons, Atoms, and Antiatoms"

Prof. Valery Nesvizhevsky

4:15 pm - 5:15 pm

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Prof. Valery Nesvizhevsky, Staff Scientist
Science Division
Institute Laue-Langevin (ILL)
Grenoble, France

Abstract:
Gravitational quantum states (GQS) are traps for ultracold massive particles with gravity on top and a specularly reflecting mirror with a sharply changing surface potential on bottom.  Ultralow energies make this system very sensitive to any tiny interactions and large sizes simplify the experimental techniques.  GQS was discovered in experiments with ultracold neutrons (UCN) in 2002 and since then, they are actively used by several research groups (qBounce, Tokyo, GRANIT) at ILL, Grenoble.

While repulsive neutron-nuclei optical potential of many materials totally reflect UCN from surfaces, attractive van der Waals/Casimir-Polder potentials can also reflect ultracold atoms and molecules at surface due to quantum reflection.  In contrast to the case of neutrons, nobody has ever observed GQS of atoms and antiatoms.  GQS and a related phenomenon of Centrifugal Quantum States (CQS) of these particles is a sensitive method for the searches for extra short-range forces arising due to yet undiscovered light bosons or other phenomena beyond the Standard Model, manifestations of extra dimensions or dark matter.  The techniques developed within GQS studies promise to help achieving ultralow energies of H thus providing unprecedented conditions for optical and hyperfine spectroscopy of H with ultimate precision, which will be pursuit within the GRASIAN project.

November 29 Colloquium Announcement

November 15, 2018

"ISEE's Professional Development Program: Preparation for Effective and Inclusive Teaching and Mentoring"

Ms. Lisa Hunter and Mr. Rafael Palomino

4:15 pm - 5:15 pm

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Ms. Lisa Hunter and Mr. Rafael Palomino
Institute for Scientist and Engineer Educators (ISEE)
University of California Santa Cruz
Santa Cruz, California

Abstract:
The Institute for Scientist and Engineer Educators (ISEE) has been working with the science, technology, engineering, and mathematics (STEM) community since 2001 to prepare early-career scientists and engineers to become effective and inclusive in their teaching and mentoring.  At the heart of this work is the Professional Development Program (PDP), which provides graduate students and postdocs intensive training in teaching methods supported by research and a practical teaching experience with students at the undergraduate level.  More than 550 participants have now completed the program and have used the experience to obtain jobs, fellowships, and grants.  Participants become part of an enduring national community of scientists and engineers dedicted to effective and inclusive education.  ISEE was recently awarded a grant from the NSF, "Advancing Inclusive Leaders in Astronomy," with an NSF physics supplement, which provides support for graduate students and postdocs at ISEE chapters to participate in the PDP and for alumni at sites across the U.S. to lead and expand upon ISEE's prior work at their own institutions.  This presentation will include information about the PDP, including research projects related to PDP thematic elements and how they increase student performance in the classroom.

The University of South Carolina is ISEE's newest chapter, currently operating in the Physics and Astronomy department with Chapter Lead and PDP alumnus, Steven Rodney.  The USC chapter will send at least one new team to the PDP in Spring 2019 and we are actively seeking student and postdoc participants as well as faculty partners.
 

November 8, 2018

"Efficient Modeling of Defects and Impurities in Semiconductors"

Prof. Sylvester N. Ekpenuma

4:15 pm - 5:15 pm

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Dr. Sylvester Ekpenuma, Professor
School of Natural Sciences and Mathematics
Claflin University
Orangeburg, South Carolina

Abstract:
Defects and impurities in materials affect their properties.  For semiconductors, these can significantly affect their electronic and structrual properties.  Given their usefulness in device applications, there has been extensive research in defects and impurities in semiconductors in order to better understand various phenomena associated with their use.  Experimental identification and characterization are challenging as defects sometimes develop even in the best experimental conditions.  Theoretical modeling has emerged as a needed complement to experimental work and computational advances have led to reasonable and accurate results that can serve as predictive tools for defect identifications.  This presentation will review some theoretical defect modeling techniques and apply the special quasi-random structures approach for the study of defects in cadmium zinc telluride.

November 8 Colloquium Announcement

November 2, 2018

Seminar:  "Heterogeneous Interfaces with High-Tc Crystalline Bi-2212 for Teasing Out Proximity and Electric-Field Screening Effects"

Prof. Arthur Hebard

2:00 pm - 3:00 pm

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Prof. Arthur Hebard
Distinguished Professor of Physics
Member of the National Academy of Sciences
University of Florida
Gainesville, FL
 
Abstract:
The crystalline layered high-Tc superconductor Bi-2212 can be easily cleaved into smoothly faceted flakes, which, when placed into intimate physical contact with a variety of layered materials or bulk semi-conductors, form heterogeneous junctions.
 
Two such junctions are discussed in this talk.  Bi-2212/1T-TAS2, the 1T-TaS2 is a Mott insulator harboring charge density waves (CDWs) and Bi-2212/n-GaAs Schottky barrier junctions, which manifest quantum mechanical tunneling at low bias voltages.  The CDW order in the 1T-TaS2 appears to play an important role by coexisting with an unexpected and surprisingly high Tc of the induced proximity gap which, for junctions with high transparencies, is seen to have a surprisingly large value (~ 20 meV) equal to half that of intrinsic Bi-2212 (~ 40 meV).  Proximity-induced high-Tc superconductivity in the 1T-TaS2 is driven by coupling to the metastable metallic phase coexisting within the Mott commensurate (CCDW) phase and associated with a concomitant change of the CCDW order parameter in the interfacial region.  For the Bi-2212/n-GaAs Schottky barrier junctions, modifications to the thermionic emission equation provide an excellent description of the I-V characteristics even at low temperatures where tunneling is found by differential conductance spectroscopy measurements to be important and capacitance measurements under reverse bias suggest an unexpectedly long electric field screening length in the superconductor.
 

October 25, 2018

"The Star-Formation History of the Universe Revealed by Gamma Rays"

Prof. Marco Ajello

4:15 pm - 5:15 pm

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Dr. Marco Ajello, Assistant Professor
Department of Physics and Astronomy
Clemson University
Clemson, South Carolina
 
Abstract:
The light emitted by all galaxies across the history of the Universe is encoded in the intensity of the extragalactic background light (EBL), the diffuse cosmic radiation field at ultraviolet, optical, and infrared wavelengths.  The EBL is a source of opacity for high-energy γ rays via the photon-photon interaction (γγ --> e+e-), leaving a characteristic attenuation imprint in the spectra of distant γ-ray sources.
 
In this talk, I will report on unprecedented measurement of the EBL using data from the Large Area Telescope on board of Fermi, which has allowed us to measure the star-formation history and the density of faint galaxies during the re-ionization.
 

October 4, 2018

"A Physics-Based Criterion for Nuclear Fusion Energy Production"

Prof. Luca Guazzotto

4:15 pm - 5:15 pm

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Dr. Luca Guazzotto, Associate Professor
Department of Physics
Auburn University
Auburn, Alabama
 
Abstract:
Nuclear fusion energy production has been the ultimate goal of an active field of research for several decades.  In addition to the technological and physics challenges that need to be overcome to achieve fusion energy production, some considerations at a macroscopic level are also necessary.  In particular, a precise energy balance needs to be satisfied in order to achieve net energy production.  The so-called "Lawson criterion," derived from the original work by Lawson in 1957, has been for decades the de-facto standard of our understanding of energy balance in nuclear fusion reactors and experiments.
 
In this talk, we will review the basis for energy balance and power production in fusion devices and discuss the details of the Lawson criterion.  In the last part of the talk, we will highlight some of the recent improvement and extensions to the Lawson criterion that will allow us to gain a better understanding of the requirements for fusion energy production.
 

September 27, 2018

"Superfluid Universe, the Ground State in Quantum Gravity, and Gravastars"

Prof. Pawel Mazur

4:15 pm - 5:15 pm

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Dr. Pawel Mazur, Professor
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
I will talk about superfluid universe, the ground state in quantum gravity, and gravastars.  Quantum mechanical considerations applied to the largest physical system in evidence have led to the understanding that there must exist such a thing as vacuum energy, which in its ground state should be homogeneous and isotropic, but in the presence of "impurities" (baryons), it will exhibit inhomogeneities.  Superfluid is a condensate.  Considering droplets of such a condensate, one arrives at the concept of a gravastar, the maximally supercompact material configuration consistent with the laws of graviation.  It just happens that such objects are abundant in the Universe.  There is one in the Center of the Milky Way galaxy known as the Sag A*, which has a mass of approximately 4.4 million Solar masses.  The Event Horizon Telescope (EHT), a planet-wide array of radio telescopes, will either refute or confirm predictions following from the gravastar theory of super-compact objects in our Universe in the next few years.

September 20, 2018

"Dark Matter from Z to A and Beyond:  The History and Status of Direct Searches"

Prof. Frank Avignone, III

4:15 pm - 5:15 pm

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Dr. Frank Avignone, III, Carolina Endowed Professor of Physics and Astronomy
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
The discovery that there was far more mass in galaxies than contained in visible material was made by Fritz-Zwicky in 1933.  He drew this conclusion by observing the motions of galaxies in the Coma Cluster and by applying the virial theorem.  He concluded that there was several hundred times more mass in the Cluster than could be accounted for by the mass in stars and dust.  He called this unobserved mass "Dunkel Materie" in his native Bulgarian language.  Following the publication of his results, there were a number of other observations that clearly support this conclusion.  We will review the other observations and then discuss the history of the experimental direct searches from the first one published in 1986, to the many efforts ongoing today.  In particular, the roles played by members of the USC Department of Physics and Astronomy in the past and present experiments will be discussed.
 

September 6, 2018

"Quasar Outflows and Their Contribution to Galactic-Scale Feedback Processes"

Prof. Nahum Arav

4:15 pm - 5:15 pm

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Dr. Nahum Arav, Professor
Department of Physics
Virginia Polytechnic Institute
Blacksburg, Virginia
 
Abstract: 
Quasar outflows are a prime candidate for producing various galactic-scale feedback processes:  explaining the relationship between the masses of the central black hole and the galaxy's bulge, and chemically enriching the Intra-cluster medium.  Using the Hubble Space Telescope, we observed the first sample of quasar outflows that covers the 500-1050 Angstrom rest-frame spectral region (XUV).  These observations are revolutionizing our understanding of the outflows and their influence on the host galaxy.  XUV coverage is the only way to probe the very high ionization phase that carries 90% or more of the outflowing material, and obtain the distances of each outflow from the central source.  The survey uncovered three outflows, which are likely to have the largest outflow kinetic-luminosity measured to date.
 

April 26, 2018

"Gluon Imaging"

Prof. Yordanka Ilieva

4:15 pm - 5:15 pm

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Dr. Yordanka Ilieva, Associate Professor
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
Gluons mediate the strong interaction that binds visible matter and, together with quarks, are the building blocks of all hadrons.  Thus, the study of gluons is of fundamental importance for understanding the strong dynamics that gives protons, neutrons, and nuclei their basic properties.  Among the gauge bosons in the Standard Model, gluons are the only self-interacting particles.  The gluon self-interaction causes effects that are unique for strongly-interacting matter and are not observed in electroweak phenomena.  One such effect is confinement, meaning that no single quark or gluon can be observed in isolation.  The practical experimental consequence of confinement is that one cannot break a proton or a neutron into quarks and gluons and study these constituents directly.  Special imaging techniques need to employed in order to construct the three-dimensional maps of gluons in nucleons and nuclei and to explore the interactions between gluons and their contribution to the nucleon-nucleon force.  While deep inelastic inclusive reactions have been instrumental to study the longitudinal momentum distributions of gluons, the measurements of certain exclusive nuclear reactions allow to obtain information about how the gluons are distributed in space in a plane perpendicular to the parent nucleon or nucleus motion.
 
In this talk, we will present a program that is being carried out at Jefferson Lab to study the transverse gluon structure of proton, neutron, and deuteron in fixed-target experiments.  This is accomplished by scattering a photon beam off a fixed proton or deuteron target and detecting in coincidence an outgoing intact proton or deuteron and a J/y meson.  We will also discuss high-precision gluon imaging planned with the next large U.S. nuclear-physics installation, the Electron-Ion Collider (EIC).
 

April 19, 2018

"The Clouds Around Our Galaxy"

Prof. Robin Shelton

4:15 pm - 5:15 pm

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Dr. Robin Shelton, Professor
Department of Physics and Astronomy
University of Georgia
Athens, Georgia
 
Abstract:
Sensitive observations have found enormous clouds of material beyond our Milky Way Galaxy.  Some are as large as mini-galaxies with as much mass as 100 million Suns.  Others are shreds that were ripped from nearby galaxies.  Additional observations show that several nearby clouds are currently interacting with our own Galaxy.  Some have reportedly shot through the Milky Way's disk while others are currently passing through the less dense outskirts of our Galaxy.  My group has been computationally modeling these clouds, called high velocity clouds (HVCs), in order to determine how they affect our Galaxy and how our Galaxy affects them.

In this presentation, I will show how HVCs behave on timescales of hundreds of millions of years, how they shed streamers of highly ionized gas that become incorporated into our Galaxy, and what happens when they collide with the dense gas in our Galaxy's disk.

April 19, 2018 Announcement

April 12, 2018

"The (76)Ge Program to Search for Neutrinoless Double-Beta Decay"

Prof. Vincente Guiseppe

4:15 pm - 5:15 pm

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Dr. Vincente Guiseppe, Assistant Professor
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton number violating process, and the effective Majorana neutrino mass.  The MAJORANA Collaboration is operating its DEMONSTRATOR array of high-purity Ge detectors at the Sanford Underground Research Facility in South Dakota to search for neutrinoless double-beta decay in (76)Ge.  A similar experiment by the GERDA collaboration is operating at LNGS in Italy.  The first results from the MAJORANA DEMONSTRATOR's initial 10 kg-yr of exposure has set a half-life limit on the decay while an upcoming release of the unblinded data set is planned to reach 30 kg-yr of exposure.  The MAJORANA DEMONSTRATOR and GERDA experiments have achieved the lowest backgrounds and a superior energy resolution at the neutrinoless double-beta decay region of interest.  These results demonstrate that (76)Ge is an ideal isotope for a large next generation experiment.  Building on the successes of the MAJORANA DEMONSTRATOR and GERDA, the LEGEND collaboration has been formed to pursue a ton-scale (76)Ge experiment.  This talk will present the initial results from the MAJORANA DEMONSTRATOR' experiment, the plan for the LEGEND experiment, and the role the USC group is playing in the overall (76)Ge program.
 

April 5, 2018

"Make Your Particles And Play With Them Too"

Prof. Yanwen Wu

4:15 pm - 5:15 pm

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Dr. Yanwen Wu, Assistant Professor
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
Our universe is made up of particles ranging from the fundamental few, such as quarks, to a vast sea of composites and quasiparticles, such as atoms and excitons.  While there is still much to uncover on the fundamental level, properties of particles in the composite realm are well-identified and better understood because their interaction is mediated by the ubiquitous photon.  This knowledge provides researchers in the fields of atomic and condensed matter the tools to create and manipulate quasiparticles with a high degree of precision and versatility.

In this talk, I will discuss the properties of two specific types of quasiparticles (excitons and surface plasmon polaritons) in two different condensed matter systems (semiconductor and metal) and how they can be optically measured and manipulated for potential applications in quantum information processing and nanoscale photonic circuitry.
 

March 29, 2018

"Nuclear Lattice Simulations"

Prof. Dean Lee

4:15 pm - 5:15 pm

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Dr. Dean Lee, Professor
Department of Physics and Astronomy
Michigan State University
East Lansing, Michigan
 
Abstract:
This is an introduction to how atomic nuclei and other quantum few- and many-body systems can be studied using lattice simulations.  The first part of the talk explains the basic formalism called lattice effective field theory.  The rest of the talk is a discussion of novel methods and the new physics insights one gains with each.  The methods discussed are the adiabatic projection method for scattering and reaction calculations, pinhole algorithm for probing structure and thermodynamic properties, and eigenvector continuation for extending calculations to regions of parameter space where things otherwise break down.
 

March 8, 2018

"Strange, Non-Strange, and Heavy Quark Distributions"

Prof. Sergey Alekhin

4:15 pm - 5:15 pm

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Prof. Sergey Alekhin
Deutsches-Elektronen-Synchrotron (DESY)
University of Hamburg
Institute for High-Energy Physics
Hamburg, Germany and Protvino, Russia
 
Abstract:
Results of the QCD analysis of a variety of the hard-scattering data is overviewed with a particular focus on determination of the quark distributions in the nucleon.  A potential of the recent precise data collected at the Large Hadron Collider (LHC) for the problem of quark species disentangling is discussed and compared to the impact of the low-energy fixed-target data alongside of modeling the heavy-quark contribution within various factorization schemes.  Finally, remaining challenges and potential improvements in the field are outlined.
 

March 1, 2018

"On Integrating General Relativity with Quantum Theory by Reframing Riemannian Geometry as a Generalized Heisenberg Lie Algebra

Dr. Joseph E. Johnson

4:15 pm - 5:15 pm,

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Dr. Joseph E. Johnson
Distinguished Professor Emeritus
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
For over 100 years, the dominant problem in theoretical physics has been the lack of integration of the theory of general relativity (GR) with quantum theory (QT) and the standard model (SM).  QT and the SM are built upon a non-commuting operator (Lie) algebra of fundamental observables for position, momentum, energy, angular momentum, charge, strangeness and other observables for describing atomic and nuclear level phenomena.  This algebra expresses the interference in the order of fundamental measurements. But GR is framed as nonlinear differential equations for the curved metric of space-time in a Riemannian Geometry (RG) without an operator algebra for its fundamental observables of space-time and of the metric.
 
It will be shown that the Einstein equations for GR as well as the underlying RG and can be reformulated as a generalized Lie algebra with a single assumption that generalizes the space-time metric to be a function of the position operators from quantum theory.  Since the metric is now an operator, this approach generalizes the framework of the underlying Heisenberg Lie algebra and consequently the Lorentz and Poincare algebras when gravitation is dominant.   The proposed integrated algebraic system is shown to give exactly the Einstein equations with large masses and dominant gravity (small h) and likewise to exactly give traditional QT and the SM frameworks when gravity is negligible.  Possible observable tests of this proposed integration and new results are discussed.  This approach also admits extensions to extra dimensions as with string theories.  However, some of the core problems of such an integration (renormalization, covariant GR gauge transformations and their merger with the SM Yang Mills theory) are not yet solved.  The presentation will end with a purely mathematical derivation of the foundations of RG based upon a generalized Lie algebra.
 

February 22, 2018

“Challenges for Hadron Spectroscopy”

Dr. Alessandro Pilloni

4:15 pm - 5:15 pm,

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Dr. Alessandro Pilloni
Theory Center Postdoctoral Staff
Thomas Jefferson National Accelerator Facility
Newport News, Virginia
 
Abstract:
Although QCD is universally acknowledged as the theory of strong interactions, the way how the fundamental degrees of freedom (quark and gluons) arrange themselves into the observed hadrons is still a mystery.  Moreover, the presence of multiple states leads to intricate interference patterns that make the extraction of meaningful information challenging.

In this colloquium, I will discuss the role of amplitude analysis in converting the ra experimental data into robust physics information.  I will finally present some of the phenomenological models used to describe the features of the spectrum.
 

February 15, 2018

“The Search for the Invisible Axion: The Current Status of ADMX”

Dr. David B. Tanner

4:15 pm - 5:15 pm,

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Dr. David B. Tanner, Professor
Department of Physics
University of Florida
Gainesville, Florida

Abstract:
The Axion Dark Matter eXperiment (ADMX) is conducting a search for axions within the dark-matter halo of our Galaxy.  The nature of the dark matter in the Universe, one of the most compelling questions in all of science, will be clarified by the results of this search.  Dark matter makes up roughly 85% of the mass in the universe and we don’t know what it is.  It interacts extremely weakly with the ordinary matter and energy in the universe, making detection very challenging.  Axions are a very well-motivated candidate for the dark matter.  Many would say these days that they are the best-motivated candidate.  Axions can be detected by their conversion to microwave photons in a strong magnetic field; this process is the basis of many searches for axions and axion-like particles.

The ADMX experiment employs a large-volume superconducting magnet, a high-Q tunable microwave cavity, an ultrasensitive SQUID microwave amplifier, and a high-performance dilution refrigerator to enable 100 mK temperatures for cavity and SQUID.  In the last year, this “Generation 2” ADMX detector has reached the sensitivity to detect axions even in the case where they are as weakly coupled as theory allows.  The ADMX detector, located at the University of Washington, has just completed its first run at this design sensitivity. There were no detections and the search continues with a second science run.  The resulting limits on axion mass, the prospects for the ongoing search, and the outlook for the future will be discussed.
 

February 1, 2018

“Assembling the Future Through Control of Nanoscale Interfaces”

Dr. Andrew B. Greytak

4:15 pm - 5:15 pm,

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Dr. Andrew B. Greytak, Assistant Professor
Department of Chemistry and Biochemistry
University of South Carolina
 
Abstract:
The behavior of 0, 1, and 2-dimensional nanoscale materials is strongly influenced by surface structure that is subject to exchange with the surrounding environment. Analysis of the surfaces of materials of different dimensionalities can require considerably different approaches, but common to all are shared concepts of charge balance, coordination chemistry, and crystallography; and shared goals and challenges in developing scalable approaches to sensors and optoelectronic devices. In this talk, I will focus on two areas of ongoing research in our lab.
 
In the first area, we are developing gel permeation chromatography as a multifunctional processor for purification and ligand exchange chemistry of a variety of compound semiconductor nanocrystals, including fluorescent quantum dots (QDs). GPC serves as a valuable tool in preparing ligand-exchanged quantum dots with diverse functions including water solubility, and in providing a well-defined initial state for thermodynamic investigations. I will emphasize the use of GPC to study ligand exchange through on-column reactions between QDs and small molecules. I will also discuss nascent efforts to improve understanding and performance of assembled QD films (nanocrystal solids) as solution-processable semiconductor materials.
 
In the second area, we are using functional imaging to study ligand association to semiconductor nanowires, host-guest interactions in 1D microporous crystals, and optoelectronic properties of epitaxial graphene/silicon carbide (EG/SiC)-based nanoelectronic heterostructures. I will emphasize recent results from scanning photocurrent microscopy on EG/SiC bipolar phototransistors.
 

January 15, 2018

“70 Years of Physics”

Dr. Ronald D. Edge

4:15 pm - 5:15 pm,

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Dr. Ronald D. Edge
Distinguished Professor Emeritus
Department of Physics and Astronomy
University of South Carolina
 
Abstract:
The Cavendish Lab, my old haunt, recently informed me that they were building their third generation.  Since I am of the first generation founded in 1871, I had better hurry up and tell about it.  My friend, GFC Searle, knew Clerk Maxwell, the first professor, personally.  Maxwell was very humorous, unlike his picture.  Searle also founded the V2 V Club.  I went there just after the war, when there was no heat.  Taking notes while wearing woolly gloves is not easy, even if lectures were from Bragg, Dirac, and Hartree (using the Schroedinger approach).  My research employed the 1 MeV Philips Cockcroft-Walton accelerator, which looked like something from Frankenstein and worked like that too.

Going to Australia in 1954, I re-built the Harwell electron synchrotron at the new Australian National University for photodisintegration.

Coming to USC in 1958, the department was converting from a teachers' training college to a research institution.  Unfortunately, the new department head had died in the summer, Tony French had inherited the job, and he invited me.  We commenced a Ph.D. program that year and acquired two graduate students. Theorists may only require pencil and paper, but experimentalists are more demanding.  The NSF gave us funds for research on cosmic ray neutrons, and a small accelerator, for which the state provided a building.  The first summer, the entire department camped there as it was the only building where air conditioning was available.  USC had an enrollment of 3,000 students at the time, which has now increased to approximately 50,000 between all state campuses.
 

January 18, 2018

“News from PICO and COHERENT”

Dr. Juan I. Collar

4:15 pm - 5:15 pm,

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Dr. Juan I. Collar, Professor
Kavli Institute for Cosmological Physics
University of Chicago
Chicago, Illinois
 
Abstract:
I will discuss the most recent results from PICO, a search for particle dark matter using rather unconventional bubble chambers.  I will then move on to COHERENT, an ongoing effort at ORNL's Spallation Neutron Source seeking to exploit the recently-measured coherent neutrino-nucleus scattering (CEvNS) as a new tool for neutrino physics.  The common ground between these two projects is the detection of keV and sub-keV nuclear recoils.  The challenges in developing and understanding detector technologies sensitive to these will be emphasized.