Seminars and Colloquia, July through December, 2016

• This Week's schedule.
• Earlier Semesters.
• Typical Week's schedule.
• July 4-8, 2016's schedule.
• July 11-15, 2016's schedule.
• July 18-25, 2016's schedule.
• July 25-29, 2016's schedule.
• August 1-5, 2016's schedule.
• August 8-12, 2016's schedule.
• August 15-19, 2016's schedule.
• August 22-26, 2016's schedule.
• August 29-September 2, 2016's schedule.
• September 5-9, 2016's schedule.
• September 12-16, 2016's schedule.
• September 19-23, 2016's schedule.
• September 26-30, 2016's schedule.
• October 3-7, 2016's schedule.
• October 10-14, 2016's schedule.
• October 17-21, 2016's schedule.
• October 24-28, 2016's schedule.
• October 31-November 4, 2016's schedule.
• November 7-11, 2016's schedule.
• November 14-18, 2016's schedule.
• November 21-25, 2016's schedule.
• November 28-December 2, 2016's schedule.
• December 5-9, 2016's schedule.
• December 12-16, 2016's schedule.
• December 19-23, 2016's schedule.
• December 26-30, 2016's schedule.

Seminars and Colloquia, Typical Week:

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Journal Club on Statistical Mechanics, Condensed Matter Physics, and Optics (Informal):

Oklahoma State Physics Department

Seminars and Colloquia, July 4-8, 2016

Physics PhD Thesis Defense:

Physics PhD Thesis Defense:

Oklahoma State Physics Department

Seminars and Colloquia, July 11-15, 2016

Physics PhD Thesis Defense:

Oklahoma State Physics Department

Seminars and Colloquia, July 18-22, 2016

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, July 25-29, 2016

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, August 1-5, 2016

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, August 8-12, 2016

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, August 15-19, 2016

First Week of Classes

Joint Physics Colloquium and Chemistry Seminar:

Abstract:

Quantum stability of atomic and electronic structure of low-dimensional structures is the key point since the discovery of a variety of 1D and 2D nanowires, nanotubes, one-atom thick films (e.g. graphene and h-BN) and complex low-dimensional heterostructures. The great progress to describe and interpret the structure and properties of low-dimensional nanostructures has been achieved by electronic structure calculations of perfect 1D and 2D infinite crystalline lattices, for which an implementation of periodic boundary condition approximation can cause artificial structural and magnetic order stabilization. There are several basic mechanisms of structural and magnetic order instability of low-dimensional structures. In particular, quantum destabilization of atomic structure of low-dimensional nanoclusters with multiple non-equivalent sublattices can be caused by translation symmetry breakdown. The asymmetry of zig-zag h-BN, h-SiC or fluorinated nanoribbon edges causes a uniform structural curvature with considerable out-of-the-plane bending, which results in breakdown of translational periodicity. Another mechanism of translational symmetry breakdown in low-dimensional carbon pentagon-constituted nanostructures with multiple sp²/sp³ sublattices. It was found that finite nanoclusters suffer strong uniform unit cell bending followed by breaking of the crystalline lattice linear translation invariance. At one-electron level of theory, a perfectly flat lattice is just a regular point on a potential energy surface with non-zero derivative, rather than an extreme point like global or local minimum or transition state. The lattice bending along two perpendicular directions leads to formation of nanotubes with potential energy crossing at zero curvature. Application of von Neumann–Wigner theorem to large-diameter tubes proves that 2D sp²/sp³ nanostructures are correlated transition states between two symmetrically equivalent bent structures.

Note: Refreshments will be served in Physical Sciences Room 147 at 3:00 PM.

Oklahoma State Physics Department

Seminars and Colloquia, August 22-26, 2016

Second Week of Classes

Oklahoma State Physics Department

Seminars and Colloquia, August 29-September 2, 2016

Condensed Matter Physics Seminar:

Abstract:

Raman spectroscopy plays a key role in studies of graphene and related carbon systems. Graphene is perhaps the most promising material of recent times for many novel applications, including electronics. In this talk, I will present how the traditional and well established Kramers–Heisenberg–Dirac (KHD) Raman scattering theory (1925–1927) was extended to crystalline graphene.

Oklahoma State Physics Department

Seminars and Colloquia, September 5-9, 2016

Labor Day Break: Monday, September 5

Physics Colloquium:

Dr. Quarles is the 2016 Physics Distinguished Alumni & Hall of Fame Inductee.

Introduction: A Random Walk: From OSU to OSA

My path from student in Stillwater to Chief Scientific Officer at The Optical Society in Washington, DC will be reviewed briefly before presenting my colloquium.

Abstract:

The thrust of this overview will focus on transparent polycrystalline optical materials, ranging from laser hosts to scintillators to window and dome materials. Comparisons of the spectroscopic, mechanical, thermo-optic and laser performance properties between single crystal and ceramic oxide gain materials will be presented. The first demonstration of laser-grade optical ceramics took place in 1995 by Ikesue with Nd-doped YAG. Over the past decade, a number of studies have shown that there are several techniques for processing the nanopowders that are the precursors to the fabrication of the polycrystalline laser hosts. Unique characteristics include achieving higher doping levels of the laser active impurities than can typically be obtained through standard Czochralski crystal growth techniques. Other unique manufacturing opportunities include uniform distributions of the active ions across the entire cross section of the polycrystalline pieces. Transparent ceramics can be produced by starting with phase-pure-oxide powders, or by several different reactive approaches in which a mixture of metal oxides are sintered. Utilization of these various nanopowder preparation technologies has led to advanced development and demonstration of large-scale materials utilized in scintillator applications, or as transparent optics on various military platforms. The rapid global growth and characterization of these materials over the past twenty years will be highlighted. The applications of these polycrystalline materials will be reviewed to provide a context for next-generation evolutions of various laser, imaging and transmissive optical systems.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, September 12-16, 2016

No talks scheduled.

Oklahoma State Physics Department

Seminars and Colloquia, September 19-23, 2016

Physics Colloquium:

Abstract:

My talk will discuss basic principles and technical aspects for the production of positron emitting radioisotopes for human use using a medical cyclotron.

Short Bio:

Carlos received a Master’s Degree in 1979 and a Doctoral Degree in Physics in 1983 from Instituto Balseiro and Centro Atómico Bariloche in Argentina. He spent four years as a postdoctoral and research assistant professor with the University of Tennessee, Knoxville working at Oak Ridge National Laboratory. After three years in private industry, he joined the University of Pennsylvania in 1991 as an Assistant Professor and Cyclotron Facility Manager where he developed and collaborated to develop new manufacturing techniques for PET radiopharmaceuticals. In 1998, he moved to The University of Texas Houston as an Associate Professor and Director of the Cyclotron Facility. He applied and obtained the first Nuclear Pharmacy License for distribution of [¹⁸F]FDG in the state of Texas. In 2002, he founded Cyclotope, a private nuclear pharmacy specializing in manufacturing of PET radiopharmaceuticals for routine clinical use and research purposes. He was president of Cyclotope until 2010 when he was appointed as Professor in Experimental Diagnostic Imaging and Nuclear Medicine at MD Anderson Cancer Center where he currently serves as Director of the Cyclotron Radiochemistry Facility.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, September 26-30, 2016

Physics Colloquium:

Abstract:

Orbital is a degree of freedom independent of charge and spin, which plays important roles in magnetism and superconductivity in transition-metal-oxides. Recently, cold atom optical lattices have provided a new opportunity to investigate orbital physics. In this talk, we will present novel features of orbital physics that are not easily accessible in solid state systems.

We predicted that bosons, when pumped into high orbital bands of optical lattices, exhibit a class of novel superfluid states with complex-valued condensate wavefunctions spontaneously breaking time-reversal symmetry. These states are beyond the scope of the “no-node” theorem which applies to most well-known states of bosons. They exhibit unconventional symmetries in analogy to those of unconventional superconductivity. Our prediction has been experimentally observed by Hemerich’s group at Hamburg, who verified the p-wave symmetry through matter-wave interference and time-of-flight measurements. For orbital fermions, we focus on itinerant ferromagnetism (FM), i.e. FM with Fermi surfaces, which is a hard-core problem of strong correlation physics. The mean-field type Stoner criterion neglects correlation effects and thus too much overestimates the FM tendency. In fact, even under very strong repulsions, typically electrons in solids usually remain paramagnetic. Furthermore, the Curie–Weiss metal phase above Curie temperature is also a long-standing problem exhibiting a dichotomic nature: The spin channel is local moment-like and incoherent while the charge channel remains coherent. In spite of these difficulties, based on unambiguous non-perturbative studies, we predict the existence of the itinerant FM phase with high Curie temperatures in the p-orbital bands. We established a series of theorems proving the ground state FM phase over a large region of fermion fillings and performed sign-problem free quantum Monte-Carlo simulations. The critical and finite-size scalings of magnetic phase transitions are performed based on which Curie temperatures are extracted at high numeric precisions. Our results also apply to certain types of d-orbital transition-metal oxides in solid state systems.

1. Congjun Wu, Unconventional Bose–Einstein Condensations Beyond the “No-node” Theorem, Mod. Phys. Lett. 23, 1 (2009), a brief review.
2. Yi Li, E. H. Lieb, Congjun Wu, Exact Results on Itinerant Ferromagnetism in Multi-orbital Systems on Square and Cubic Lattices, Phys. Rev. Lett. 112, 217201 (2014).
3. Shenglong Xu, Yi Li, Congjun Wu, Thermodynamic properties of a 2D itinerant ferromagnet — a sign-problem free quantum Monte Carlo study, Phys. Rev. X 5, 021032 (2015).

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, October 3-7, 2016

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Abstract:

I will discuss some of the open technical issues for DUNE and how they are being addressed, especially through the ProtoDUNE program at CERN.

Physics Colloquium:

Abstract:

I will discuss the physics and technology of DUNE, the DEEP Underground Neutrino Experiment.  DUNE will be a groundbreaking experiment for long-baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches.  Planning of DUNE continues to proceed rapidly.  The DUNE Far Detector will consist of four 10-kiloton fiducial volume modular liquid argon time-projection chambers (LArTPC) placed deep underground at the Sanford Underground Research Facility in Lead, South Dakota, USA.  The Far Detector will be coupled to the LBNF multi-megawatt wide-band neutrino beam planned for Fermilab.  The LArTPC technology allows for detailed reconstruction of neutrino interaction and nucleon decay final states over an energy range from a few MeV to many GeV, providing high resolution vertex determination, precision charged particle tracking, particle identification, and calorimetry.  Photon detector systems embedded within the LArTPC add precise timing capabilities for non-beam events.  Designs for both single phase and dual phase LArTPC have reached advanced stages; and these designs will be tested through a full-scale prototyping program called ProtoDUNE, to be executed at CERN over the next few years.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, October 10-14, 2016

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Abstract:

The discovery of the Higgs boson in 2012 has led to dramatic consequences for natural extensions of the Standard Model. In these extensions, such as the minimal supersymmetric and composite Higgs models, light, colored top-quark partners are required in order to minimize the tuning in the Higgs potential. The fact that they have not yet been seen has increased the stakes for naturalness. I will discuss the prospects for discovering these particles at Run 2 of the LHC and the implications for naturalness, including the possibility that the Higgs potential may in fact be tuned at a level never before seen in particle physics.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Fall Break: Friday, October 14

Oklahoma State Physics Department

Seminars and Colloquia, October 17-21, 2016

Physics Colloquium:

Abstract:

When visualising topological objects via 3D printing, we need a three-dimensional geometric representation of the object. There are approximately three broad strategies for doing this: “Manual” — using whatever design software is available to build the object by hand; “Parametric/Implicit” — generating the desired geometry using a parametrisation or implicit description of the object; and “Iterative” — numerically solving an optimisation problem.

The manual strategy is unlikely to produce good results unless the subject is very simple. In general, if there is a reasonably canonical geometric structure on the topological object, then we hope to be able to produce a parametrisation of it. However, in many cases this seems to be impossible and some form of iterative method is the best we can do. Within the parametric setting, there are still better and worse ways to proceed. For example, a geometric representation should demonstrate as many of the symmetries of the object as possible. There are similar issues in making three-dimensional representations of higher dimensional objects. I will discuss these matters with many examples, including visualisation of four-dimensional polytopes (using orthogonal versus stereographic projection) and Seifert surfaces (comparing my work with Saul Schleimer with Jack van Wijk’s iterative techniques).

I will also describe some computational problems that have come up in my 3D printed work, including the design of 3D printed mobiles (joint work with Marco Mahler), “Triple gear” and a visualisation of the Klein Quartic (joint work with Saul Schleimer), and hinged surfaces with negative curvature (joint work with Geoffrey Irving).

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, October 24-28, 2016

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Postponed.

Physics Colloquium:

Abstract:

The gap between students’ homework grades and test scores in introductory physics courses has become a major concern for many instructors. In order to study this, in 2012 Expert TA launched its Analytics platform and entered into the arena of “Big Data.” Using this platform, we worked with instructors to do an intense analysis of data from 125 classes from the 2013-2014 Academic Year; cross-referencing an aggregate data set involving approximately 1200 assignments and 2.4 million submitted answers. We identified three major factors causing these gaps: access to immediate and meaningful feedback, practice on symbolic questions, and a minimized ability to find problem solutions online. Knowing this, we have worked to develop the largest available library of “symbolic” questions and we use Analytics to data mine every incorrect answer ever submitted, in order to continually improve our feedback for these questions. We have also established very effective strategies to guard our problem solutions. The ultimate goal is to keep students focused on the physics; and then as they are working problems to provide them with meaningful, Socratic feedback that helps resolve misconceptions. Information will also be presented regarding how instructors have used Expert TA to reduce cost to students, increase academic integrity, and improve overall outcomes during the time since that case study was performed.

Note: The traditional student-speaker chat will begin in Physical Sciences Room 147 at 3:00 PM. All students are welcome! Refreshments will be served.

Oklahoma State Physics Department

Seminars and Colloquia, October 31-November 4, 2016

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Oklahoma State Physics Department

Seminars and Colloquia, November 7-11, 2016

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Postponed.

Oklahoma State Physics Department

Seminars and Colloquia, November 14-18, 2016

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Physics Colloquium:

Abstract:

One-dimensional nanostructures (nanowires, nanotubes, nanosprings, etc.) hold immense technological promise, specifically, in electrical applications. This is for the obvious reason that they are amenable to applying electrical contacts, i.e. building a device or sensor. At first blush, one would assume that in order to observe the rich physics of electron transport in these structures that devices must be constructed from a single nanostructure. I will demonstrate through a review of a number of experiments that this is not always true. I will present experiments with ZnO coated silica nanosprings, both for a single nanospring device and a random array of these structures, that the same physics and electron transport is observed. Furthermore, highly sensitive gas sensing can be achieved with a random array of nanostructures and that understanding their sensing capabilities requires one to consider the morphology of the array. In the end, I hope to have demonstrated that the choice of device design, a single 1-D nanostructure or an array, requires an understanding of the physics of their electronic transport and the phenomena you want to explore.

Note: Refreshments will be served in Physical Sciences Room 147 at 3:00 PM. All students are welcome!

Oklahoma State Physics Department

Seminars and Colloquia, November 21-25, 2016

Physics Colloquium:

Abstract:

Astronomer have incontrovertable evidence of Dark Matter from collisions of galactic clusters, from rotation curves of galaxies, and from gravitational lensing. The protons, neutrons, and electrons forming stars, planets, intergalactic gas and people account for only 15% of the mass of the entire Universe. Dark Matter is still known almost exclusively from it’s gravitational influence, but if ordinary matter feels gravity plus at least the three known forces, perhaps there are analogous Dark Side forces. At CERN’s Large Hadron Collider (LHC), the hunt is on for the Dark Photon, a gauge boson akin to the electromagnetic photon, but mediating a conjectured Dark Force between Dark Matter particles. This talk will describe the ATLAS experiment’s search for Dark Photons using LHC collision data, and it will include home movies from inside the ATLAS experiment.

Note: Refreshments will be served in Physical Sciences Room 147 at 3:00 PM. All students are welcome!

Thanksgiving Break: November 23-25

Oklahoma State Physics Department

Seminars and Colloquia, November 28-December 2, 2016

Physics Colloquium:

Abstract:

Neutrinos are the lightest particles now known to have mass.  Many parameters of the neutrino sector have now been measured using neutrinos from the sun, cosmic rays hitting the atmosphere, nuclear reactors and particle accelerators.  Several well-defined but accessible questions remain to be answered.  After reviewing the status of neutrino physics in 2016, I’ll look forward to how one present and one future long-baseline neutrino experiment can answer those questions.  NOvA is an off-axis neutrino experiment currently running using neutrinos from Fermilab and a detector in Northern Minnesota.  The new large international DUNE collaboration has been formed to conduct an ambitious program of neutrino and underground physics using a new beam from Fermilab to the Sanford Underground Research Facility (SURF) in South Dakota.  DUNE is planned to be the highest priority project in particle physics in its time frame.

Note: Refreshments will be served in Physical Sciences Room 147 at 3:00 PM. All students are welcome!

Oklahoma High Energy Physics Seminar on Talk-Back Television:

Abstract:

This presentation will review the latest results of Higgs boson search in ATLAS in one of the most important and still undiscovered channel : VH with H→bb. An overview of the 3 channels analysis (leptonic decays only of the vector boson V) will be shown as well as the Standard Model constraint checks that have been performed.

Oklahoma State Physics Department

Seminars and Colloquia, December 5-9, 2016

Finals Week

No talks scheduled

Oklahoma State Physics Department

Seminars and Colloquia, December 12-16, 2016

No talks scheduled

Oklahoma State Physics Department

Seminars and Colloquia, December 19-23, 2016

No talks scheduled

Oklahoma State Physics Department

Seminars and Colloquia, December 26-30, 2016

No talks scheduled

Last Updated:

jhhp@jperk.phy.okstate.edu