Fall 2016

September 2, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: Department Panel
Host: Physics Chair Gene Tracy
Abstract: Panel Discussion about department followed by 1st social event of the year. PGSA/SPS/Dept join

September 9, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: Jason McDevitt, William & Mary
Title: Commercialization of Technology Developed at W&M
Abstract: I will discuss patents and commercialization of inventions, both on a general level and more specific to W&M.  Additionally,  I will talk about startup companies and the logistics of getting a company started and then funded, as well as the relative advantages and disadvantages of trying to spin companies out of W&M.
Jason McDevitt's Presentation (pdf)

September 23, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: Hebin Li, Department of Physics, Florida International University, Miami, FL 33199, USA
 Host: E. Mikhailov
Title:  Optical Multi-dimensional Coherent Spectroscopy 
Abstract: The concept of multi-dimensional coherent spectroscopy originated in nuclear magnetic resonance (NMR) where it revolutionized NMR studies of molecular structure and dynamics. In the past two decades, the same concept has been implemented in the optical region with femtosecond lasers. In the experiment, the nonlinear response of a sample to multiple laser pulses is measured as a function of time delays. A multi-dimensional spectrum is constructed by taking a multi-dimensional Fourier transform of the signal with respect to multiple time delays.
In this presentation, I will introduce optical multi-dimensional coherent spectroscopy and its applications to study atomic vapors and semiconductor nanostructures. Atomic vapors provide a simple test model to validate the method, while the obtained 2D spectra reveal the surprising collective resonance due to the dipole-dipole interaction in a dilute gas. By extending the technique into a third dimension, 3D spectra can unravel different pathways in a quantum process and provide complete and unambiguous information to construct the full Hamiltonian of the system. Besides atomic vapors, optical multi-dimensional coherent spectroscopy is also a powerful tool for studying many-body dynamics and coupling in solid-state systems such as semiconductor nanostructures. I will present several applications in semiconductor quantum wells and self-assembled quantum dots, where unique information about the systems can be obtained from 2D spectra. The technique will also have advantages in studying valley carrier dynamics in atomically thin 2D semiconductors.  

October 7, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: Dr. Douglas Higinbotham, Jefferson Lab
Host: T. Averett
Title: The Proton Radius Puzzle
Abstract: Recent atomic physics measurements using the Lamb shift in Muonic hydrogen have determined the proton's charge radius to be 0.84 fm, while the radius determined from atomic hydrogen Lamb shift and modern electron scattering measurements give a value of 0.88 fm. As the proton has only one true radius, this systematic difference in the radius from different measurement techniques has become known as the proton radius puzzle. I will discuss the strengths and weaknesses of the Muonic hydrogen measurements compared to atomic hydrogen. I will also summarize the history of the electron results, starting from the 1963 review article on nuclear physics electron scattering data by Hand et al. with its 0.81(1)fm 

standard dipole radius, and track the evolution of the proton charge radius up to the recent 0.88(1)fm results from Mainz. I will then discuss the statistical methods that were used by groups in Virginia (JLab, UVA, and W&M) that yield an electron scattering result that is in agreement with the Muonic hydrogen results. Finally, I will discuss  how these results could bring about a change to the Rydberg constant.

October 28, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Atsushi Fukuyama, Department of Nuclear Engineering, Kyoto University, Kyoto, Japan
Hosts: S. Sen and G. Vahala
Plasma, Nuclear Fusion, and Integrated Modeling of Fusion Plasmas
Abstract: Plasma is a state of matter composed of mobile charged particles, electrons and ions, globally keeping electrical charge neutrality. The state of plasma prevails in universe; sun, fixed stars, their surroundings, and interstellar space. The sun is a high-temperature plasma sustained by nuclear fusion reaction as an energy source. It is emitting a broad range of radiation and also energetic charged particles called a solar wind, which produces auroras in the polar regions of the earth. In addition to natural plasmas including lightening, man-made plasmas have been widely used for lighting, welding, and micro processing. The most intensive plasma research, however, has been made for the quest of a nuclear fusion reactor as a sustainable energy source. Nuclear fusion is a nuclear reaction in which light atomic nuclei are combined to form a heavier nucleus and a lighter nucleus or a neutron. Though the reaction requires a collision of nuclei with large relative kinetic energy, it produces much more energy due to the difference of total mass, in other words, binding energy. The most easily accessible fusion reaction on the earth is considered to be that of a dueteron (D) and a triton (T) which are the nuclei of the isotopes of hydrogen, dueterium and tritium. This reaction generates a 3.5 MeV helium nuclei, alpha particle, and a 14.1 MeV neutron. DT fusion reactor requires a high-temperature fuel plasma, above 10 keV, and good confinement of plasma in order to sustain the fusion reaction. The confinement performance is usually evaluated by the product of fuel ion density and energy confinement time. For realizing good confinement of charged particles, various kinds of magnetic confinement devices have been developed. The best confinement results have been obtained in tokamak devices which contain axi-symmetric doughnut-shaped plasmas. In order to analyze various physics phenomena in tokamak plasmas and predict the performance of future fusion reactors, reliable computational tool which self-consistently describes whole plasma over whole discharge is required. Integrated modeling of fusion plasmas is in progress for this purpose including the analyses of dynamical equilibrium, global stability, transport, heating, fueling, and so on. We are developing an integrated tokamak modeling code TASK with advanced features, and have applied for the analysis of various tokamaks. Some results of kinetic transport modeling and kinetic full wave analyses will be presented.

November 4, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: Jianwei Qiu, Jefferson Lab
Host: C. Carlson
Exploring the fundamental properties of matter with an Electron-Ion Collider
The proton and neutron, known as nucleons, are the fundamental building blocks of all atomic nuclei and make up essentially all the visible matter in the universe, including the stars, the planets, and us. The nucleon is not static but has complex internal structure, the dynamics of which are only beginning to be revealed in modern experiments.  The nucleon emerges as a strongly interacting, relativistic bound state of quarks and gluons in Quantum Chromodynamics (QCD), the theory of the strong force.  In this talk, I will demonstrate that the proposed Electron-Ion Collider (EIC) with its unique capability to collide polarized electrons with polarized protons and light ions at unprecedented luminosity, and with heavy nuclei at high energy, will be the most powerful tomographic scanner able to precisely image quarks and gluons inside the proton and nuclei. This precision microscope will allow us to “see” and explore the dynamics binding quarks and gluons together to form hadrons. The EIC will address the most compelling unanswered questions in QCD and hadron physics, and take us to the next QCD frontier.
REFERENCE: A. Accardi et al., “Electron Ion Collider: The Next QCD Frontier - Understanding the glue that binds us all,” Eur. Phys. J. A52, 268 (2016) [arXiv:1212.1701 [nucl-ex]] 
November 11, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: Kenneth Burch, Boston College
Host: I. Novikova
Title: Search for New Excitations in Topological Places

Abstract:  In recent years the desire to find new modalities of computation has pushed efforts to find new platforms for quantum information processing. Particularly attractive are topological states, where new long range and protected entanglement should be possible. The excitations needed also require understanding and controlling entirely new states of mater. In this talk, I will outline why materials with strong spin-orbit coupling and electron correlations are quite promising in this regard. In particular they could precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid states. Such states are predicted to produce Majorana Zero modes, whose statistics are direct evidence of the topological nature of the ground states. In this talk I will briefly outline our efforts to pursue novel quasi‐particles at the interface between high Tc superconductors and topological insulators. I will then focus on our efforts to find a Kiteav quantum spin liquid and its associated fractional excitations in RuCl3. Specifically using IR and Raman spectroscopy we have confirmed this material has the right ingredients. Most interesting Raman provides direct evidence for the fractional nature of the excitations. However the material reveals low temperature magnetic order, as such I will also discuss our efforts to search for a true spin liquid in this material via mechanical exfoliation.

November 18, 2016 (Friday) 4:00-5:00p.m. Small Hall 111
Speaker: TBA