Fall 2015

September 11, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Crystal Bailey, APS
Host: Prof. Wouter Deconinck
Title: Breaking the Myth of the "Non-Traditional" Physicist: The Real Story About Employment for Physics Graduates

Abstract: Physics degree holders are among the most employable in the world, often doing everything from managing a research lab at a multi-million dollar corporation, to developing solutions to global problems in their own small startups. Science and technology employers know that with a physics training, a potential hire has acquired a broad problem-solving skill set that translates to almost any environment, as well as an ability to be self-guided and -motivated so that they can teach themselves whatever is needed to be successful at achieving their goals. Therefore it's no surprise that up to 70% of physics graduates find employment in private sector, industrial settings.

Nevertheless, few students graduate with a robust awareness of careers outside of the academic realm, or with additional skills which will increase their workforce competitiveness among other STEM graduates. In this talk, I will explore less-familiar (but more common!) career paths for physics graduates, and will provide information for students--and their faculty mentors--on how we can do more to prepare our students for a diverse range future career outcomes.
Dr. Bailey's Presention
Dr. Bailey's Video Presention (YouTube)

September 18, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Kunio Sayanagi, Hampton University
Host: Prof. Wouter Deconinck
Title: Hexagon and Polar Vortex: Observing Saturn's Northern High Latitudes from NASA's Cassini Orbiter
Abstract: NASA's Cassini Orbiter is now in its 11th year of orbiting Saturn. When it arrived Saturn in 2004, the northern hemisphere was in winter, and the north polar region was shrouded in the winter polar night and was not observable in visible night. Saturn underwent equinox in 2009, and the sun started shining on the north pole for the first time since 1994,
revealing many features in the northern high-latitudes such as the north-polar vortex and the famous hexagonal cloud feature that encircles the pole at 75 degree N. I will give an overview of the latest observation results delivered by the Cassini orbiter from Saturn.

September 21, 2015 (Monday) 4:00-5:00p.m. Small Hall 111

Speaker: Warren Wesley Buck III, University of Washington, Brothell
Host: Prof. E. Tracy
Title: An Interplay of Physics and Art
Abstract: Often thought of as disparate subjects, physics and art have deep connections. For centuries, scientists and physicists in particular indulge their “downtime” with playing music and making art. It has actually been thought that possessing the talents to perform physics and making of art were not connected; but rather the person so doing such things was considered extremely talented. Certainly the tools used are vastly different, yet the creative elements employed in performing both have similarities: especially the strong drive to express a language thru which one can communicate what one “sees” in our immediate environment and beyond. Certainly, making the connection between physics and music is apparent thru considering wavelengths, amplitudes and what not. In this talk I will touch on the creative aspects via some of the temporal areas when a break thru in physics/STEM leads to breakthroughs in visual arts and vice versa.

September 25, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Nina Markovic, Goucher College
Host: Prof. Enrico Rossi
Title: Designing quantum matter with superconducting nanowires
Abstract: Superconducting nanowires are an experimental realization of a model quantum system that features collective degrees of freedom and exhibits a host of non-equilibrium and non-local phenomena. The nature of superconductivity in nanowires is uniquely sensitive to size and shape quantization, coupling with the environment and proximity effects. In this talk, I will describe how we can utilize these features in order to tailor the superconducting properties of nanowires in desirable ways. Specifically, we have developed novel methods for fabrication of ultranarrow nanowires with precisely controlled normal resistance and consistent superconducting properties. In magnetic field, the superconductivity in nanowires is affected by vortices, topological excitations that look like small whirlpools of supercurrent. I will show how the texture of the superconducting wavefunction can be precisely controlled by the size, shape, magnetic field and tunable interfaces with different materials.

October 2, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Alex Radovic, William & Mary Physics Department
Host: Prof. Tricia Vahle
Title: Studying Neutrino Oscillations at the NOvA Experiment
Abstract: The observation of neutrino oscillation provides evidence of physics beyond the standard model, and the precise measurement of those oscillations remains an important goal for the field of particle physics. NOνA will soon be one of the foremost experiments in that field. Taking advantage of a two-detector technique, a tightly focused off-axis view of the NuMI neutrino beam, and a pair of finely instrumented liquid scintillator detectors, NOνA is in a prime position to contribute to precision measurements of the neutrino mass splitting, mass hierarchy, and delta cp. This presentation will describe the goals and design of the NOνA experiment, show first results obtained while the detectors where still being constructed, and outline what to expect from NOvA in the coming years.

October 9, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Erin Ryan, NASA Goddard
Host: Prof. Wouter Deconinck
Title: Asteroids and Comets: Keys to understanding the early Solar System and Exoplanetary Systems

Abstract: Recent searches for exoplanetary systems from ground based telescopic surveys and the Kepler mission have shown that planetary systems are common within our galaxy, however the current configuration of our solar system may not be an accurate prototype for other planetary systems. In particular, the discovery of a number of hot Jupiters have been found at distances from their host stars that confounds the current planet formation models unless a form of planetary migration is invoked. Concurrently with the first hot Jupiter detections, the planetary science community recognized the potential for planet migration to shape our own Solar System. Numerous lines of evidence within the Solar System suggest that giant planet migration had a significant impact on shaping the dynamical orbits and small body populations we witness today.

Although the planets have undergone alteration due to heating and differentiation, the compositions of the small bodies in the solar system can be treated as time capsules from the early epoch of planet formation. The compositions of comets and asteroids are key to understanding planetary migration in our solar system, and even how volatiles such as water could have been transported from the outer reaches of Kuiper Belt into the inner solar system. I will discuss results on comet and asteroid compositions and the boundaries they place on planetary migration models and the origin of volatiles in the inner solar system.

October 16, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Prof. Eden Figueroa, Department of Physics and Astronomy, Stony Brook University
Host: Prof. Eugeniy Mikhailov
Title: Building an elementary quantum processor using single photons and atoms
Abstract: Quantum engineering is the design and testing of devices that can perform the tasks needed to achieve operational quantum information processing and computing. These novel devices have tasks conceptually similar to their well-known classical counterparts, but rather different physical implementation. Successfully interconnecting many of these quantum devices is the key to bring about the first generation of quantum processing machines. In this elementary architecture, some individual devices need to be able to receive, store and retrieve photonic qubits (quantum memories), while other nodes must be geared toward the manipulation of qubits (quantum gates).

In this talk I will present our recent results towards the construction of an elementary quantum processor capable of storing and processing photonic polarization qubits. First, I will show our implementation of room temperature quantum memories [1]. Secondly, I will discuss how we have benchmarked the performance of atomic vapor interfaces as possible quantum gates [2]. Lastly, I will present the interconnection of two light matter interfaces forming a small quantum network [3].
[1] Scientific Reports 5, 7658 (2015).
[2] arXiv:1505.03918 (2015).
[3] PRA A 92, 033846 (2015).

October 30, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Prof. Vera Smolyaninova, Department of Physics, Astronomy, and Geosciences, Towson University
Host: Prof. Mumtaz Qazilbash
Title: Metamaterial Superconductors

Abstract: Superconducting properties of a material, such as electron-electron interactions and the critical temperature of superconducting transition may be expressed via the effective dielectric response function of the material. Such a description is valid on the spatial scales below the superconducting coherence length (the size of the Cooper pair), which equals ~100 nm in a typical BCS superconductor. Searching for natural materials exhibiting larger electron-electron interactions constitutes a traditional approach to high temperature superconductivity research. Recently developed field of electromagnetic metamaterials deals with somewhat related task of dielectric response engineering on sub-100 nm scale. The metamaterial approach to dielectric response engineering may considerably increase the critical temperature of a composite superconductor-dielectric metamaterial. Moreover, this approach has been verified in experiments with compressed mixtures of tin and barium titanate nanoparticles of varying composition and in experiments with core-shell aluminium-aluminum oxide metamaterials. We have demonstrated that Al₂O₃-coated aluminium nanoparticles may form the recently proposed epsilon near zero (ENZ) core-shell metamaterial superconductor with a T_C that is three times that of pure aluminium. IR reflectivity measurements confirm the predicted metamaterial modification of the dielectric function thus demonstrating the efficacy of the ENZ metamaterial approach to T_C engineering. These results open up numerous new possibilities of considerable T_C increase in other simple superconductors.

November 6, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Mark Pederson, Department of Chemistry, Johns Hopkins University
Host: Prof. Shiwei Zhang
Title: Self-Interaction Corrected Density-Functional Theory with Unitary Invariance: Applications to Molecular Magnets

Abstract: Molecular magnets generally consist of a collection of transition-metal ions that have five to six nearest-neighbors. Due to this high-coordination, the d-level filling associated with the transition metal centers is often unambiguously determined by the ligands surrounding the metal center. As such, gradient corrected density-functionals, such as PW91 and PBE GGA[1], have proved to be very successful for describing such molecules[2]. However, improvements in these functionals are necessary if one is interested in obtaining quantitatively accurate spin excitations in molecules containing low-coordination 3d transition metal ions or, for other reasons, one is interested in understanding electronic transport across such molecules. In this talk, I review some of the general improvements that have been offered by the Perdew-Zunger self-interaction correction (SIC) and past approaches to solving these equations[3]. A new version of the self-interaction correction to density functional theory, based upon Fermi Orbitals, is briefly introduced[4-5] which seems to be simpler to use and which provides two formal improvements over the original version. Further, the formalism identifies quasi-classical electron positions that seem to be in accord with conventional classical models for electrons in molecules. Applications of this self-interaction-corrected theory, within the local spin-density approximation, give improvements to atomization energies of molecules, total energies and ionization energies in atoms, and the uniform electron gas is obtained. By example, it is shown that the method is fast enough to apply to systems with open metal centers[6].

[1] J. P. Perdew, J. A. Chevary, S. H. Vosko, K. A. Jackson, M. R. Pederson, D. J. Singh, and C. Fiolhais, Phys. Rev. B 46, 6671 (1992).
[2]N.A. Zimbovskaya and M.R. Pederson, Physics Reports 509 (1-87) (2011).
[3]M.R. Pederson, R.A. Heaton, and C.C. Lin, J. Chem. Phys. 82, 2688 (1985).
[4]M.R. Pederson, A. Ruszinzsky and J.P. Perdew, J. Chem. Phys. 140, 121105 (2014).
[5]M.R. Pederson, J. Chem. Phys. 142, 064112 (2015).
[6]M.R. Pederson, T. Baruah, D.Y. Kao and L. Basurto (To appear).

November 13, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: James Maxwell, DOE
Host: Prof. Wouter Deconinck
Title: Development of a Polarized Helium-3 Ion Source for an Electron Ion Collider

Abstract: Spin polarization of targets and beams has been a crucial tool in scattering experiment probes of nuclear structure. While the properties of the proton have allowed successful polarized proton targets and beams, neutrons are more difficult to manipulate in a particle accelerator beam. Fortunately, other materials, such as 3He, offer surrogates of the neutron to allow the creation of “effective” neutron beams to allow the study of neutron in an accelerator. We are developing a beam source of polarized 3He ions for use at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab (BNL), and at the proposed Electron Ion Collider. This source combines two existing technologies to create polarized ions which can be injected into a beamline: the technique of metastability exchange optical pumping (MEOP) is a decades old process allowing the polarization of 3He via laser pumping at low pressure in a small magnetic field; and the electron beam ion source (EBIS) currently in use at BNL can ionize and extract nearly any gas for injection into RHIC. A successful polarized 3He beam which would become a cornerstone of neutron study at RHIC and at a future electron-ion collider facility.

November 20, 2015 (Friday) 4:00-5:00p.m. Small Hall 111

Speaker: Bogdan Wojtsekhowski (JLab)
Host: Prof. Todd Averett
Title: Speed of light Isotropy and Lorentz Force

Abstract: The gravitational force at the Plank energy scale leads to a violation in the speed of light isotropy. Such a prediction and the importance of basic symmetries for fundamental forces in nature have motivated a large number of elegant experiments. The high precision limit on the speed of light anisotropy obtained by Michelson in 1887 was the primary experimental foundation for Einsteinâ€™s theory of special relativity in 1905. The much-improved measurement by Tobar and collaborators (Nature, 9/2015) achieved a sensitivity 13 orders higher than was done 130 years ago, but shows no evidence for the anisotropy in the round-trip speed of light. In this talk I will describe a concept of a new test of the prediction of the theory of special relativity, specifically a search for the Lorentz force sidereal time variation, which probes a one-way speed of light isotropy with precision approaching the onset of quantum gravity effects. I will present a concept of the experiments at Jefferson Laboratory with the 12-GeV CEBAF accelerator and at Cornell University with the CESR storage ring.

December 4, 2015 (Friday) 4:00-5:00p.m. Small Hall 110

Speaker: Prof. Anton Burkov, University of Waterloo
Host: Prof. Enrico Rossi
Title: Weyl Semimetals

Abstract: I will describe the recently discovered new state of condensed matter, Weyl semimetal. Closely related Dirac semimetals will also be mentioned. I will describe the most basic physical properties of Weyl semimetals, focusing on the properties that follow from the nontrivial electronic structure topology, e.g. the Fermi arc edge states. Novel transport phenomena, such as the large negative longitudinal magnetoresistance, characteristic of Weyl semimetals, will be described as well. I will demonstrate that these are also rooted in the nontrivial electronic structure topology. Connections to particle physics, in particular the chiral anomaly, will be discussed.