Seminars and Colloquia, January through June, 2014


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Seminars and Colloquia, Typical Week:


Oklahoma High Energy Physics Seminar on Talk-Back Television:

Date:Thursday
Time:1:30-3:00 PM
Place:106 B Studio Room, Classroom Building, OSU
& Nielsen Hall, Room 103, OU
Inquiries: kaladi.babu@okstate.edu or kao@nhn.ou.edu

Physics Colloquium:

Date:Thursday
Time:3:30-4:30 PM
Place:PS 110
Inquiries: s.nandi@okstate.edu or perk@okstate.edu

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

Date:Friday (bi)weekly
Time:2:00 PM
Place:PS 147
Inquiries: perk@okstate.edu or girish.agarwal@okstate.edu

Oklahoma State Physics Department

Seminars and Colloquia, January 1-3, 2014


No talks scheduled


Oklahoma State Physics Department

Seminars and Colloquia, January 6-10, 2014


No talks scheduled: Prelim Exams


Oklahoma State Physics Department

Seminars and Colloquia, January 13-17, 2014


No talks scheduled: First Week of Classes


Oklahoma State Physics Department

Seminars and Colloquia, January 20-24, 2014


Martin Luther King Day, Monday, January 20, 2014

Second Week of Classes


Physics Colloquium:

Speaker:Dr. Pierre Darancet
Applied Physics & Applied Mathematics Department
Fu Foundation School of Engineering & Applied Science
Columbia University, New York, NY
Date:Thursday, January 23, 2014
Time:3:30 PM
Place:PS 110
Title:Understanding Non-Equilibrium Charge Transport and Rectification at Nanoscale Interfaces

Abstract:

Understanding and controlling non-equilibrium charge transport across nanoscale interfaces and in supramolecular assemblies is central to developing an intuitive picture of fundamental processes in nanoelectronics, photovoltaics, and other energy conversion applications. In this talk, I will discuss our theoretical studies of finite-bias transport at prototypical organic/metal interfaces, single-molecule junctions, small organic molecules trapped between gold electrodes. I will show how many-body effects influence energy level alignment in these systems, and that a simple model of non-local correlations on the top of density functional theory leads to quantitative agreement with experiments [1-6]. Finally, I will discuss the implications of this theory in the context of transport in molecular diodes [7]; in particular, how to systematically optimize rectification by tuning the competing energy scales in single-molecule junctions via molecular conformation [8].

References: [1] J.B. Neaton et al. Phys. Rev. Lett. 97, 216405 (2006); [2] I. Tamblyn,, et al. Phys. Rev. B, 84, 201402(R) (2011); [3] J. Widawsky, et al. NanoLett. 12, 354 (2012); [4] P. Darancet, et al. NanoLett 12, 6250 (2012); [5] T. Kim, et al. submitted (2013); [6] B. Capozzi, et al. submitted (2013); [7] A. Aviram and M. A. Ratner, Chem. Phys. Lett. 29, 277 (1974); [8] A. Batra, et al. NanoLett. 13, 6233 (2013).

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, January 27-31, 2014


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

Speaker:Dr. Mario F. Borunda
Department of Physics
Oklahoma State University
Date:Friday, January 31, 2014
Time:12:30 PM
Place:PS 147
Title:Introduction to Graphene and Dirac Fermions

Abstract:

Join us for an informal talk discussing graphene. I will show how a plane layer of C atoms bonded together in a honeycomb lattice has become the most interesting two-dimensional system available. After an overview of its physical properties, I will use the last part of the talk to concentrate on the outstanding transport properties of graphene (some of which can be attributed to charges behaving as massless Dirac fermions). The purpose of this presentation is to introduce undergraduate and graduate students to this fascinating research subject but experts are also invited.


Oklahoma State Physics Department

Seminars and Colloquia, February 3-7, 2014


Physics Colloquium:

This week's colloquium is postponed till next week because of the weather situation.


Oklahoma State Physics Department

Seminars and Colloquia, February 10-14, 2014


Oklahoma High Energy Physics Seminar on Talk-Back Television:

Speaker:Prof. Jihn E. Kim
Department of Physics
Seoul National University, Seoul, South Korea
Date:Thursday, February 13, 2014
Time:1:30 PM
Place:106 B Studio Room, Classroom Building, OSU
& Nielsen Hall, Room 103, OU
Title:Dark Energy from Approximate U(1)de and U(1)PQ

Physics Colloquium:

Speaker:Dr. Howard A. Baer
Homer L. Dodge Professor of High Energy Physics
Homer L. Dodge Department of Physics & Astronomy
University of Oklahoma
Date:Thursday, February 13, 2014
Time:3:30 PM
Place:PS 110
Title:Supersymmetry and Dark Matter in the Post Higgs Discovery Era

Abstract:

The recent discovery of the Higgs boson at the CERN Large Hadron Collider seemingly completes the discovery of all matter states predicted by the Standard Model of particle physics. But from the theory side, it is hard to understand how the Higgs can be so light without a protective symmetry known as supersymmetry. Yet, also, no superparticles have been discovered. The Higgs mass itself provides deep clues as to where the superparticles are lurking. Current theory and experiment also point to dark matter as being comprised of an axion-higgsino mixture (two dark matter particles) and thus we might expect ultimately detection of both an axion and a weakly-interacting massive particle, or WIMP!

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, February 17-21, 2014


OSU Research Week

For details see researchweek.okstate.edu.


Oklahoma State Physics Department

Seminars and Colloquia, February 24-28, 2014


Physics Colloquium:

Cancelled and replaced by faculty meeting.


Oklahoma State Physics Department

Seminars and Colloquia, March 3-7, 2014


APS March Meeting


Oklahoma State Physics Department

Seminars and Colloquia, March 10-14, 2014


No talks scheduled this week.


Oklahoma State Physics Department

Seminars and Colloquia, March 17-21, 2014


Spring Break


Oklahoma State Physics Department

Seminars and Colloquia, March 24-28, 2014


Physics Colloquium:

Speaker:Dr. Xin Chen
Department of Radiation Oncology
School of Medicine
Stanford University
Date:Wednesday, March 26, 2014
Time:3:30 PM
Place:PS 110
Title:Monte-Carlo Based Verification of Dose Distribution and Monitor Units for Volumetric-Modulated Arc Therapy (VMAT)

Abstract:

Patient-specific verification for volumetric-modulated arc therapy (VMAT) is incapable of providing full 3D dosimetric information and is labor intensive in the case of severe heterogeneities or small-aperture beams. In this work, a cloud-based Monte Carlo (MC) dose calculation method is developed to perform the evaluation in entire 3D space and reveals the source of discrepancies between measured and planned dose. Another outstanding problem in VMAT is how to independently validate the monitor units (MUs) of the treatment plan for a patient generated by the treatment planning system (TPS). A novel MC-based framework for independent MU verification of VMAT is established. As an example of the applications, the dosimetric impact of real-time prostate motion during VMAT is assessed using this Monte Carlo dose calculation method by incorporating the interplay effect between aperture modulation and target motion.

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 High Energy Physics Seminar on Talk-Back Television:

Speaker:Dr. Seodong Shin
Department of Physics
Indiana University, Bloomington, IN
Date:Thursday, March 27, 2014
Time:1:30 PM
Place:106 B Studio Room, Classroom Building, OSU
& Nielsen Hall, Room 103, OU
Title:A Probe of the Charged Higgs from a SM Higgs to WW Search at the LHC

Oklahoma State Physics Department

Seminars and Colloquia, March 31-April 4, 2014


Physics Colloquium:

Speaker:Dr. Tianye Niu
Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
and George W. Woodruff School
Nuclear & Radiological Engineering and Medical Physics Program
Georgia Institute of Technology, Atlanta, GA
Date:Monday, March 31, 2014
Time:3:30 PM
Place:PS 141
Title:Advanced Conebeam CT Imaging for Image-guided Radiation Therapy

Abstract:

X-ray cone-beam CT (CBCT) system is becoming an indispensable modality in the image guidance for radiation therapy and other clinical procedures. Major components of a CBCT scanner include x-ray tube and large-area flat panel detector. The system is designed as open-gantry geometry to facilitate its incorporation into treatment process. The hardware configuration of CBCT enables its on-board capability to detect the two-dimensional x-ray projections passing through a large illuminated volume of an object, and then to reconstruct three-dimensional volumetric images. Thus CBCT system acquires accurate patient geometry during treatment and is applied in routine clinical procedures, such as the patient setup. Advanced clinical applications of CBCT imaging, however, are hindered by several major bottlenecks due to physical and mechanical constraints in the current system design, including the inferior image quality, high accumulated dose in repeated scans, and limited movement flexibility. The inferior image quality is mainly caused by the physical and engineering non-ideals, such as scatter photon contamination, beam hardening, mechanical and patient motion and etc. The CT number error of CBCT image is as high as 300 HU for a middle-size human torso. The high-accumulated imaging dose from the daily use of CBCT can go up to 2 Gy after a standard radiation treatment. The circular scanning geometry of CBCT on Linac restricts the coplanar imaging scheme and limited longitudinal coverage. A quantitative, safe and flexible CBCT imaging is in urgent demand for its advanced applications. In my present work, effective scatter correction method is proposed to suppress the severe shading artifacts in the CBCT images, and the CT number error is reduced to around 20 HU. Based on the compressed sensing theory, a low-dose iterative algorithm is developed to reconstruct CBCT images of high quality using no more than 30% of projections in a conventional scan. On-going work will combine the above two schemes and achieve the simultaneous image quality improvement and imaging dose reduction. More flexible scanning trajectories will be investigated to increase the longitudinal coverage and achieve the scan mode in a volume of interest. These new techniques have the potential to facilitate the advanced use of CBCT and promote the clinical outcomes.

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.


Physics Colloquium:

Speaker:Dr. Aihua Xie
Department of Physics
Oklahoma State University
Date:Thursday, April 3, 2014
Time:3:30 PM
Place:PS 110
Title:Principles and Dynamics of Proton Transfer in Proteins

Abstract:

Proton transfer is broadly employed in protein functions, not only in energy transformation but also in biological signaling and enzymatic catalysis. Unlike electron transfer which has been well understood for nearly two decades, some key questions regarding the physical mechanism of proton transfer remains elusive after extensive studies. We will report a proof of concept study on principles and dynamics of proton transfer and its applications in proteins. In addition, we will discuss how to apply time-resolved infrared structural biology to probe and explore proton transfer during protein functions.

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.


Chemistry Department Seminar:

Speaker:Dr. Jeremy Schmit
Department of Physics
Kansas State University
Date:Thursday, April 3, 2014
Time:3:30 PM
Place:PS 103
Title:Many-body Protein Systems: Challenges of Timescale and Resolution

Abstract:

The properties distinguishing one protein from another are all determined by perturbations in the sequence of amino acid side chains. This complicates many problems in protein physics, like protein folding, because there is a wide range of relevant length scales. This problem is even worse with questions involving many-body protein interactions where the system sizes are much bigger and the timescale are often much longer. In this seminar I will discuss two cases where we have used simple analytic models to reduce many-body protein systems to smaller problems that are tractable by modern computer hardware. First, pharmaceutical companies need to be able to predict the viscosity of antibody solutions in order to avoid wasting resources on molecules that will be too difficult to manufacture and deliver. We show that antibody solutions behave much like semi-dilute polymer solutions in that the viscosity is determined by molecular entanglements. These entanglements depend strongly on interactions between the antigen binding domains, which cause the antibodies to polymerize into longer structures. Secondly, there is a great need to understand the mechanism by which proteins self-assemble into disease-related aggregates called “amyloids.” We show that the long timescale characterizing amyloid assembly is caused by the exhaustive sampling required to find the ordered structure of the final aggregate. By identifying the reaction coordinate characterizing this sampling process, we can use a series of small computer simulations to probe the effects of amino acid sequence on aggregation kinetics.

Refreshments will be served at 3:00 pm in PS 117.


Oklahoma State Physics Department

Seminars and Colloquia, April 7-11, 2014


Physics Colloquium:

Speaker:Dr. Chuanwei Zhang
Department of Physics
University of Texas at Dallas
Date:Thursday, April 10, 2014
Time:3:30 PM
Place:PS 110
Title:Search for Majorana Fermions in Spin-Orbit Coupled Superfluids and Superconductors

Abstract:

Topological quantum matter has been an active research field in physics in the past three decades with numerous celebrated examples, including quantum Hall effect, chiral superconductor, topological insulator, etc. In topological materials, Majorana fermions, first envisioned by E. Majorana in 1935 to describe neutrinos, often emerge as topological quasiparticle excitations of the systems. Majorana fermions are intriguing because they are their own anti-particles and follow non-Abelian anyonic statistics. Although the emergence of Majorana fermions in any condensed matter or atomic system is by itself an extraordinary phenomenon, they have also come under a great deal of recent attention due to their potential use in fault tolerant quantum computation. In this talk, I will discuss recent theoretical and experimental progress on the search for Majorana fermions in two spin-orbit coupled systems: spin-orbit coupled degenerate Fermi gases and semiconductor/superconductor nanostructures. I will discuss the contribution of my group in this rapidly developing field.

References

  1. C. Zhang, S. Tewari, R. Lutchyn, and S. Das Sarma, Phys. Rev. Lett. 101, 160401 (2008).
  2. M. Gong, S. Tewari, C. Zhang, Phys. Rev. Lett. 107, 195303 (2011).
  3. L. Mao, J. Shi, Q. Niu, C. Zhang, Phys. Rev. Lett. 106, 157003 (2011). Editors’ Suggestion.
  4. M. Gong, G. Chen, S. Jia, C. Zhang, Phys. Rev. Lett. 109, 105302 (2012).
  5. L. Mao, M. Gong, E. Dumitrescu, S. Tewari, C. Zhang, Phys. Rev. Lett. 108, 177001 (2012).
  6. C. Qu, Z. Zheng, M. Gong, Y. Xu, L. Mao, X. Zou, G. Guo, C. Zhang, Nature Communications 4, 2710 (2013).
  7. Y. Xu, R. Chu, C. Zhang, Phys. Rev. Lett. 112, 136402 (2014) Editors’ Suggestion.

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, April 14-18, 2014


Physics Colloquium:

Speaker:Dr. Jorge A. López
Department of Physics
University of Texas at El Paso
Date:Thursday, April 17, 2014
Time:3:30 PM
Place:PS 110
Title:Neutron-Rich Nuclear Physics

Abstract:

Modern nuclear facilities are producing neutron-rich nuclei and using them in collisions to study reactions with neutron-rich nuclei.  In this talk the study of neutron-rich systems with molecular dynamics will be presented.  In particular, neutron star crusts have been studied and found to form non-uniform nuclear structures known as “nuclear pasta” due to their shapes like “meat-pie”, “lasagna-like” layers, “spaghetti-like” rods, and “meatball-like” clumps.

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.


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

Speaker:Dr. Jorge A. López
Department of Physics
University of Texas at El Paso
Date:Friday, April 18, 2014
Time:11:30 PM
Place:PS 147
Title:Phase Changes in Nuclear Matter

Abstract:

Low temperature systems composed of neutrons and protons exhibit crystalline phases around saturation densities that go from FCC to SC.  At sub-saturation densities molecular dynamics simulations indicate that a phase transition occurs from the crystalline phase to a mixture of liquid-gas phases.  These changes, however, depend strongly on the ratio of protons to neutrons.


Oklahoma State Physics Department

Seminars and Colloquia, April 21-25, 2014


Physics Colloquium:

Speaker:Dr. Bruce J. Ackerson
Department of Physics
Oklahoma State University
Date:Thursday, April 24, 2014
Time:3:30 PM
Place:PS 110
Title:Cream Patterns in Empty Coffee Cups

Abstract:

One day I noticed by chance a strange symmetric pattern of cream in the bottom of an empty coffee cup. With awareness aroused, I found that similar patterns occurred quite often. Why do such patterns form from the well-mixed coffee and cream left at the bottom of the cup?

This talk examines possible causes for the pattern formation: evaporation, Rayleigh–Bénard convection, Maragoni convection, Soret diffusion, Rayleigh–Taylor instability, etc. These mechanisms describe non-equilibrium phenomena capable of spontaneous pattern formation. Analysis of related dimensionless numbers, still photos, and time lapsed movies provides answers.


http://youtu.be/ws1j4Sg28uo

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, April 28-May 2, 2014


Prefinals Week


Oklahoma State Physics Department

Seminars and Colloquia, May 5-9, 2014


Finals Week

No talks scheduled.


Oklahoma State Physics Department

Seminars and Colloquia, May 12-16, 2014



Oklahoma State Physics Department

Seminars and Colloquia, May 19-23, 2014


No talks scheduled.


Oklahoma State Physics Department

Seminars and Colloquia, May 26-30, 2014


No talks scheduled.


Oklahoma State Physics Department

Seminars and Colloquia, June 2-6, 2014



Oklahoma State Physics Department

Seminars and Colloquia, June 9-13, 2014


No talks scheduled.


Oklahoma State Physics Department

Seminars and Colloquia, June 16-20, 2014



Oklahoma State Physics Department

Seminars and Colloquia, June 23-27, 2014



Oklahoma State Physics Department

Seminars and Colloquia, June 30-July 4, 2014



Last Updated: .

This page was prepared by Helen Au-Yang and Jacques H.H. Perk.

jhhp@jperk.phy.okstate.edu