Physics Colloquium Series

Following a suggestion of David Bohm’s, I will explore the possibility that phenomena associated with entanglement and complementarity in quantum mechanics intimate a fundamentally non-spatiotemporal ordering to reality by looking at low-dimensional examples of systems that reproduce the relevant phenomena. I argue that this is a relatively unexplored path to explaining quantum correlations and give some philosophical motivation.

While 27% of the Universe is made of dark matter, the particle identity of the dark matter still remains a mystery. Collider studies offers a complementary tool to explore the nature of the dark matter, in addition to dark matter direct and indirect detections. In this talk, I will discuss the collider studies of the dark matter, focusing on how to observe dark matter signals, and how to distinguish dark matter scenarios. I will cover the model-independent approach for the monojet/monophoton plus missing ET signals, as well as model-dependent signatures of dark matter produced in the cascade decay chain of parent particles.

Since the discovery of superconductivity in A3C60 (A=K, Rb) in 1991 it has been debated whether the superconductivity is being driven by electron-phonon interactions, as in the standard BCS theory, or whether it is driven by electron-electron interactions, within a theory that is yet to be discovered. A second question that has also perplexed scientists, theorists and experimentalists alike, is: why is superconductivity limited to molecular valence of 3? Why is the 3 the magic number? I will give a single answer to both questions within a theory that we have developed over the past year. It gives an entirely new perspective to correlated-electron theory of superconductivity.

CERN's Large Hadron Collider (LHC), the world's most powerful particle accelerator, has completed its first run. We are beginning to address one of the most exciting and fundamental questions about nature: the nature of electroweak symmetry breaking. Many open questions remain after the discovery of the Higgs boson. I will begin by explaining these issues. Then I will describe how these questions can be answered in the challenging environment of the LHC

The Cosmological Evolution Survey (COSMOS) involves the largest contiguous region of the sky ever imaged by HST. It was motivated by the study of galaxy evolution and morphology but the combination of depth, breadth and extensive multiwavelength data makes it the best region in the sky for a comprehensive study of AGN. Using deep X-ray data in the field, over 800 AGN have been spectroscopically confirmed, and the survey has particular sensitivity to low black hole mass, low accretion rates, and high levels of obscuration. A limiting accretion rate of L/L_Edd = 0.01 is seen, below which the flow may be advective. Analogs to the Milky Way black hole at z = 2 can be detected. A study of host galaxies suggests that the AGN triggering occurs on kiloparsec scales within the host. Fitting SEDs shows that the spectral components are predictable enough to efficiently select AGN below the limit of spectroscopy on large telescopes, extending this work to even lower black hole masses. The eventual goal is a complete census of intermediate mass black holes at redshifts 1-3, which is required to tell the complete story of the co-evolution of galaxies and black holes.

Turbulent flows are found throughout nature, yet a deep physical understanding of the nature of turbulence stubbornly remains “the most important unsolved problem of classical physics” [attributed to Feynman]. But turbulence is not only a classical phenomenon. It has long been studied in superfluid helium, where quantum mechanics and quantized vortices enable means of characterizing turbulent flows not found in classical physics. Research is now beginning to address a new corner of the turbulence puzzle: two-dimensional quantum turbulence, with particular focus on atomic Bose-Einstein condensates (BECs). Within this field, prospects are emerging for obtaining a clear understanding of the relationships between elements of turbulence, such as energy spectra and the microscopic dynamics and structure of vortices, and characteristics both unique to BECs and analogous to those of 2D classical turbulence have been observed. In this talk I will describe some of these experimental, numerical, and theoretical studies in progress at the University of Arizona and collaborating institutions. My goal is to convey the notion that BECs provide exciting means of examining the links between turbulence in the quantum and classical worlds. Such studies may help foster new insights into broader aspects of turbulence physics.

Talking is a human activity controlled by the motor system which contracts muscles to produce movement of various anatomical structures. Unlike most human motor activities, however, the goal of talking is to produce a highly-structured sound wave that carries information coded as the vowels and consonants of a language. The human sound production system is comprised of vibratory and turbulence-based sound sources that induce pressure waves that propagate through the airspace of the vocal tract formed by the relative positions of the tongue, jaw, lips, and velum. Precise control of the vocal tract configuration is of critical importance for producing the desired acoustic characteristics of speech. The pattern of acoustic resonances generated by a given vocal tract shape influences vowel and consonant identity, as well as the overall sound quality (timbre). This talk will focus on the acoustic characteristics of the vocal tract that allow it to be globally shaped for vowel production and locally constricted to generate consonants. A computational model of the speech production process will be used to demonstrate samples of simulated speech.

Whether it is instruction on topics from biology, political science, engineering, economics, mathematics, business or physics, students often struggle to develop a deep understanding of the discipline knowledge and skills we hope they will master in our courses. There is a rich body of research from which to make informed decisions when creating instructional environments designed to elevate student achievement beyond what is typically achieved in the lecture-centered classroom. In addition to, getting a handle on the conceptual and reasoning difficulties held by your students, knowing which instructional materials you wish to employ, and thinking about the assessments you will use to guide your instruction or measure achievement, faculty need to think carefully about their complex classroom environment (and student population) which presents its own unique issues. For over 15 years members of the Center for Astronomy Education (CAE) at the University of Arizona have led nationwide research programs to investigate issues of teaching and learning over a wide range of STEM disciplines. The results from this research have been used to inform the development of innovative instructional strategies proven to intellectually engage learners and significantly improve their conceptual understanding, reasoning abilities, discipline skills, and attitudes regarding the role of STEM in society. In this talk I will share some of these research results, model several instructional strategies, discuss ways this work is forging a new instructional-model for surviving in extreme learning environments (such as teaching the universe in one semester to 1000 students at a time), and frame how this work provides a vehicle for changing scientific, economic and mathematical literacy across the nation.

This talk focuses on the dynamics of an important bacterial pathogen, Xylella fastidiosa within artificial plant xylem. The bacterium is the causative agent of a variety of diseases that strike fruit bearing plants including PierceÕs disease of grapevine. Biofilm colonization within microfluidic chambers was visualized in a laboratory setting, showing robust, regular spatial patterning. We also develop a mathematical model, based on a multiphase approach that is able to capture the spacing of the pattern and points to the role of the ex- opolymeric substance as the main source of control of the pattern dynamics. We concentrate on estimating the attachment/detachment processes within the chamber since these are two mechanisms that have the potential to be engineered by applying various chemicals to prevent or treat the disease.

Understanding thermal transport and thermoelectric effects at the nanoscale is a scientific challenge with important consequences both for practical applications in energy conversion/management and for the fundamental conceptual development of fields such as nonequilibrium thermodynamics. Recent advances in thermal microscopy, where spatial and thermal resolutions of 10nm and 15mK, respectively, have been achieved, raise a fundamental question, "On how short a length scale can a statistical quantity like temperature be meaningfully defined?" We tackle this question theoretically by first providing a physically motivated and mathematically rigorous definition of an electron thermometer as an open third terminal in a thermoelectric circuit. We then develop a realistic model of a scanning thermal microscope (SThM) with atomic resolution, operating in the tunneling regime in ultrahigh vacuum, including the thermal coupling of the probe to the ambient environment. With this model of an electron thermometer, we investigate the temperature distributions in molecular junctions and graphene nanoribbons under thermal bias. We find that the temperatures of individual atomic orbitals (or bonds) in these systems exhibit quantum oscillations; quantum interference mimics the actions of a Maxwell Demon, allowing electrons from the hot electrode to tunnel onto the temperature probe when it is at certain locations near the molecule, and blocking electrons from the cold electrode, or vice versa. A crossover to a classical temperature distribution consistent with Fourier's law of heat conduction is predicted as the spatial resolution of the temperature probe is reduced.

Organic nanostructures are employed in various nonlinear optical applications including novel IR mode-locked fiber lasers, all-optical switching, and 3D updateable holographic display technology. This presentation will focus on our advances in this area including, 1. Sources: Using fiber taper based carbon nanotube saturable absorber, we have demonstrated an all-fiber thulium-doped wavelength mode-locked laser operating near 2 µm with over 50nm tuning range. 2. All-optical switching: Liquids such as CCl4, CS2, and organic solutions in liquid core optical fiber (LCOF) offer an effective platform to study nonlinear optical phenomena, e.g. Raman scattering, four-wave mixing and supercontinuum generation. In these devices the long interaction length is combined with a strong field confinement to enable extremely low power operation. Our observation of all-optical switching using inverse Raman scattering in LCOF with > 20dB contrast at a time scale < 5ps will be described. 3. 3D holographic display: The use of organics and nanostructures in holographic updateable 3D display will be summarized.

Each year, for about four weeks at a time, the Large Hadron Collider (LHC) at CERN is configured to collide heavy nuclei producing beams with energy perhaps never before present in the Universe. We use large particle detectors and frontier experimental techniques to understand properties of quark gluon plasma (QGP), a new phase of matter recreated in these experiments. It is very likely that QGP was present in early Universe, till about 30 microsecond after the Big Bang. In this talk I will introduce the overall laboratory research program and present some of recent results. QGP is formed in laboratory with temperature millions times the temperature in the interior of the Sun and it exhibits many unusual properties which I will describe. For example, QGP is capable to slow down or absorb very energetic partons and significantly modify the production of particles containing heavy bottom and charm quarks. I will also discuss the relevance of the anisotropy in particle production to diagnose properties of strongly interacting matter.

The 1937 theoretical discovery of Majorana fermions (particles that are their own anti-particles) has since impacted diverse problems ranging from neutrino physics and dark matter searches to the quantum Hall effect and superconductivity. This talk will survey recent advances in the condensed matter pursuit of these elusive objects. In particular, I will discuss new ways of "engineering" Majorana platforms using exceedingly simple building blocks, along with pioneering experiments that have made impressive progress towards realizing Majorana fermions in the laboratory. These developments mark the first steps of a fascinating research program that could eventually overcome one of the grand challenges in the field - the synthesis of a scalable quantum computer.

Prof. Erich Varnes of the University of Arizona will give a talk for the general public entitled "The Higgs Boson: A Smashing Discovery". Prof. Varnes will describe the science and implications of this recent discovery that received worldwide attention in the media. A distinguished particle physicist, Prof. Varnes will convey the excitement of capturing this most elusive building block of nature.

Ultrafast laser spectroscopy is commonly used to study dynamical processes happen in the time scale of femtoseconds (10-15 s) to picoseconds (10-12 s). When probing complex systems with many degrees of freedom, however the 1D spectrum is usually congested with contributions from many structural components. Multidimensional coherent spectroscopy is a way to overcome this problem by spreading the spectral information in two or more frequency axes. In this part, I will focus on two-dimensional (2D) laser spectroscopy which can provide an incisive tool to probe the electronic transitions, and energetic evolutions in ultrafast time scales. I will demonstrate its application to the study of organic dye Coumarin 102. This 2D spectroscopy method could monitor the energy level broadening and observe time evolution. This dynamic information will help to determine the energy and charge transfer pathways in molecular systems. In biomedical research intravital two-photon fluorescence microscopy has provided insightful information on dynamic processes in vivo. However the use of exogenous labeling agents limits its applications. I will first demonstrate in vivo mouse mast cells imaging using endogenous tryptophan as the fluorophore for immunological research. Laser beam scanning is required in most current two-photon microscopes to achieve 2D images. Based on temporal focusing of femtosecond laser pulses a new type of two-photon microscope can achieve 2D images without scanning the laser beam; therefore it could reach hundreds frames/second imaging speed. To acquire depth information, most modalities still need to move the sample stage mechanically. In temporal focusing two-photon microscope changing the group velocity dispersion of the femtosecond laser pulses could lead to the displacement of the plane of the temporal focus along the optical axis from the geometrical focus of the objective lens, yielding z-scanning as a function of dispersion. Currently my group is developing pulse shaping technique with spatial light modulators (e.g. acousto-opto modulators) to electronically control the dispersion of the femtosecond laser pulses in spectral domain to achieve fast 3D fluorescence imaging.

Oak Ridge National Laboratory, a Department of Energy multiprogram science and technology lab, is home to "Titan", currently the world's fastest supercomputer. Titan is the first major supercomputing system to utilize a hybrid architecture with both conventional 16-core AMD Opteron CPUs and NVIDIA Tesla K20 GPU accelerators on 18,688 compute nodes. This talk will present trends evolving in high-performance computing resulting in systems like Titan, and the new programming models and tools available to use these new architectures. I will also discuss the impact of Titan in the theoretical low-energy nuclear physics community to achieve scientific breakthroughs in nuclear structure and reaction calculations.

The compact source of radio emission known as Sagittarius A* marks the location of the Milky Way's central supermassive black hole. The energy liberated by the growth of black holes has the power to shape whole galaxies, even clusters of galaxies, but our black hole is extremely under-luminous for its mass, radiating just 10^-9 of its Eddington luminosity. The physics of this faint emission and even the structure of the emitting region remain disputed, while observations intended to clarify the picture have only made it murkier. I will present a program to understand Sgr A* through observations at (mostly) submillimeter wavelengths, a special place in the spectrum where a combination of instrument capabilities and source physics allow us to study the emission just outside the event horizon. I will review the prospects for studying accretion physics and General Relativity itself through this object. In particular, I will review two impending experiments. The first, provided by nature, is a large accretion event that will occur this year as a cloud of gas impacts the black hole. The second, the Event Horizon Telescope project, will unite telescopes from Arizona to the South Pole to make the first resolved images of the event horizon.

The physics of natural systems is often highly influenced by spatial dimensionality from the nature of phase transitions to the properties of materials. These effects may arise from symmetries or conservation laws. Fluid turbulence is central to transport and mixing in many contexts from atmospheres and oceans to internal combustion vehicles. Turbulence in three spatial dimensions reflects the net transfer of kinetic energy from large scales to small scales where it is dissipated as heat. In contrast, conservation laws in two dimensions lead to a very different scenario, namely that energy flows to larger scales whereas the flow to smaller scales is dominated by a process of vortex gradient stretching. I will discuss the characteristics of 2D turbulence and its applicability (or not) to atmospheres and oceans where lateral extent is large compared to vertical height. Because 2D turbulence technically only occurs in a computer, quasi-2D experiments that are well described by 2D turbulence phenomenology suggest its relevance to real physical systems. In particular, I will describe experiments in flowing soap films and in electrically forced thin salt layers that show remarkable correspondence to the theory and numerical simulation of 2D turbulence.

Symmetries play an ubiquitous role in physics. Faced with the intractable task to understand the spectrum of heavy nuclei, Wigner introduced ensembles of Hamiltonian matrices that are as unconstrained as possible - hence with randomly distributed matrix elements - up to symmetry requirements of time-reversal symmetry and/or spin rotational symmetry. The ensuing random matrix theory was further extended to unitary matrices by Dyson and later to the theory of quantum transport via the formulation of the latter in terms of scattering matrices. Considering time-reversal, spin-rotational, particle-hole and chiral symmetries, quantum systems are classified into ten different symmetry classes. I will review this classification, discuss the enormously successful random matrix theory of transport and move on to more recent investigations showing how topologically nontrivial phases of matter emerge in some of these symmetry classes, depending on the system's dimensionality.

The confluence of particle physics and astrophysics has ushered in an exciting new frontier field by the name "particle astrophysics". While the birth of particle astrophysics dates back to Victor Hess's historic discovery of cosmic rays in 1912, the past 20 years has seen burgeoning research activities. But what can particle astrophysics do for you? In 2003 the Turner Committee charged by the US National Research Council (NRC) released its formal report after 3 years of investigation: "Connecting Quarks with the Cosmos: Eleven Science Questions for the New Century", in which particle astrophysics occupies the center stage for addressing the listed 11 big questions. Aspired by such calling, many universities in the world have established new dedicated centers to compete for the leadership in this field, including the Leung Center for Cosmology and Particle Astrophysics (LeCosPA) founded by the National Taiwan University (NTU) in 2007. In this talk we will introduce the topic with a historic perspective and motivate it by reviewing its science potentials. We then introduce the activities at NTU LeCosPA. In five years, it has launched vigorous theoretical and experimental programs, including the balloon-borne ANITA project in Antarctica to search for ultra-high energy cosmic neutrino, the ARA Cosmic Neutrino Observatory at the South Pole that will become the world's largest neutrino observatory when completed, and the UFFO satellite GRB telescope that aims at detecting the very initial GRB light curves within one second of the burst event. We will review the progress of these projects and their future prospects.

Lyme disease is the most prevalent vector-borne disease in the United States, and it is rapidly growing in terms of both cases identified per year and the extent of the country that is affected by the disease. But, that's not why we study it. The disease is caused by a fascinating bacterium, Borrelia burgdorferi, that is a perplexing work of biological engineering. The bacterium is able to move from the midgut of a tick into and through mammals and then back to the tick. This enzootic cycle requires that the bacterium is able to traverse a wide range of complex physical environments, from viscous fluids, like the blood, to polymeric networks and cellular layers. The bacterium's movement through these environments is produced by creating a traveling wave undulation that propagates down the length of the cell. I will discuss the physics by which the bacterium creates and maintains its shape and how it produces these traveling body waves. I will then describe experiments and modeling that have identified some aspects of the motility of these bacteria in viscous fluids and through gelatin, a mimic of the extracellular matrix in our bodies. Finally, I will describe a model for the migration and subsequent immune response that occur during the early stages of infection and may explain the advent of the characteristic Lyme disease rash.

Localization phenomena play an important role in our understanding of the properties of graphene and topological insulators. I discuss localization at the edge of bilayer graphene and the edge of two-dimensional topological insulators. In bilayer graphene subject to a strong perpendicular magnetic field we have found that in the presence of a strongly disordered edge a sequence of localized states appears. Interestingly the localization length depends only on the size of the bulk gap but is otherwise universal, i.e. independent of the type and strength of the disorder. The appearance of these localized states reflects the marginal topological properties of bilayer graphene, a bipartite square lattice with similarly disordered edges does not show such states. In two-dimensional topological insulators such as HgTe/CdTe there exists a pair of protected chiral edge states. However, if time-reversal symmetry is removed by the application of a magnetic field the protection is removed and these states localize. We investigate the divergence of the localization length as the magnetic field tends to zero.

Abstract: Atmospheric aerosols, including dust and clouds, play a significant but under appreciated role in our lives. For example, clouds reflect much of the incoming solar radiation thereby cooling the planet; while air molecules and atmospheric aerosols and may selectively scatter sunlight thereby leading to clear blue skies and beautiful red sunsets In this talk, Betterton provided an overview of the origins and nature of atmospheric aerosols and introduced some of the basic physics that explains their interesting properties and effects including "ship tracks," dust storms, visibility, health effects, and pollen. He also showcased some of the fascinating aerosol research being conducted by UA scientists. Presented November 2, 2012.

Abstract: This talk is divided into two parts. In the first part, a review was given of a notion of gravitational mass of a composite classical body as well as discuss experiments, which test a combination of the Newton gravitation and quantum mechanics. In particular, what was reproduced was the well known result that averaged over time gravitational mass of a composite classical body is related to its energy by the Einstein equation, E=m_gc^2. In the second (original) part, a problem about gravitational mass of a composite quantum body was considered, using the simplest example - a hydrogen atom. Shown was that gravitational mass operator of the atom does not commit with its energy operator, taken in the absence of gravitational field. Despite this fact, using the quantum viral theorem, it confirmed a validity of the Einstein equation in a quantum case at a macroscopic level (i.e., for the corresponding expectation values) with the accuracy 10^-18. On the other hand, it was shown that the above discussed equation is broken at the microscopic level due to quantum fluctuations. In particular, it demonstrated that such seldom events, where the Einstein equation for gravitational mass and energy does not work, can be detected by measuring unusual electromagnetic radiation, emitted by a macroscopic ensemble of hydrogen atoms. The suggested experiment can be done by using spacecraft or satellite on the Earth's orbit, provided that the atoms are supported and moved in the Earth's gravitational field with a constant velocity. If such measurements are done, to the best of our knowledge, it will be the first experiments, where some non-trivial combination of general relativity and quantum mechanics is tested. Presented October 26, 2012.

Abstract: The Standard Model of particle physics has been successfully tested experimentally for over 30 years with no discrepancies. Yet a key piece of the Standard Model, and one needed to provide mass to elementary particles, remained undetected. Experimental evidence from the ATLAS experiment at the CERN LHC for the production of a new neutral boson was presented. The production and decay of this particle is compatible with Standard Model Higgs boson. Additional measurements expected using the full 2012 data set were discussed. Presented October 12, 2012.

Abstract: On July 4, 2012, the ATLAS and CMS collaborations at the CERN Large Hadron Collider (LHC) announced the discovery of a particle consistent with the long-sought Higgs boson. As the CERN Director General Rolf Heuer put it: "We have reached a milestone in our understanding of Nature." The high-energy physics community has been much excited about it ever since. Why is it so? What is this long-sought Higgs boson? What has it told us and will tell us? In this colloquium, I would like to share a reminiscence about the developments of those most profound concepts in modern theoretical physics: the spontaneous symmetry breaking, the Goldstone theorem, the Higgs mechanism, and the prediction for the Higgs boson and the associated new physics in the Tera scale, which have led to the way the largest scientific project in history, the LHC, and to the monumental achievement in understanding of Nature. Presented October 5, 2012.

Abstract: Since its introduction in 1988, the weak value has made a remarkable progression within the scientific world. This talk delineated each step of this progression, displayed in four steps. The first step is the notion of a weak value in itself, the second is the first experiment together with the theoretical challenges, the third is acceptance as a phenomena and further experiments, and the fourth is the use of weak values as a tool for bother the further understanding of quantum puzzles and for precision measurements. Recent theoretical developments in the field will also be addressed. Presented September 21, 2012.

Abstract: Most of the matter in the Universe is made from stuff we know, and experiments aiming at the discovery of the Dark Matter from a buzzing field of physic research. Prof. Lang reviewed what a variety of astrophysical observations tell or don't tell us about the Nature of all this Dark Matter. Weakly Interacting Massive Particles (WIMPs) are a prime Dark Matter candidate, and he summarized the basic ideas of their formation and detection. The focus of this talk was will be on the experiential techniques that are used to attempt the direct detection of WIMPs with laboratory-scale detectors, together with the current status and data from running detectors. In particular, XENON100 is currently the most sensitive experiment, its principles, data, results, together with a sketch the near-future XENON1T detector. Presented September 14, 2012.

Abstract: Somewhat ironically, after the successful resolution of the solar neutrino problem appeared to confirm the standard solar model, some cracks have appeared in that model. Recent improvements in the description of the Sun's photosphere have resulted in a significant downward revision in the solar surface metallicity. In the context of the standard solar model, this requires a corresponding reduction in interior metallicity that then places the model in conflict with what is known about solar sound speeds. Haxton discussed an alternative possibility, that the Sun is not homogeneous because its surface compassion was perturbed 4.6 billion years ago by the large-scale segregation of metals that accompanied planetary formation. Haxton discussed two other problems that may be impacted by this conjecture, the systematic differences between the composition of our Sun and that of "solar twins" and the anomalous composition of Jupiter. He described a new solar neutrino detector now under construction in Canada that will directly measure the primordial C and N content of the solar core, thus testing assumption of a primordial homogeneous Sun. If the surface metallicity of a host star is altered by planetary formation, a new tool may be available for identifying systems likely to harbor exoplanets. Presented September 7, 2012.

Abstract: Attosecond XUV spectroscopy is a powerful new technique for real-time probing of electronic processes in atoms, molecules and materials. Sandhu began by outlining the basic concepts of attosecond science along with some background information on its development and progress. Physicists have applied attosecond pulse trains to problem the electronic states of atoms subjected to strong laser fields. Sandhu described the measurements which reveal quantum interferences in photoionization pathways, and have implications for the attosecond control of light-matter interaction. Next, he discussed ultrafast dynamics in molecules, which are more complex due to the coupling between electronic and nuclear degrees of freedom. He described how physicists utilized attosecond XUV pulses to measure the predisssociation and auto ionization rates in super excited molecules. Measurements addressed two long-standing questions on the relaxation dynamics of super excited oxygen, which could not be resolved in conventional synchrotron studies. In the last part of the talk, he introduced the latest efforts on the use of ultrafast techniques to understand the electron and phono dynamics in carbon nano materials and their molecular fragments. Presented August 31, 2012.

Abstract: The Lorentz law of force is the fifth pillar of classical electrodynamics, the other four being Maxwell's macroscopic equations. The Lorentz law is the universal expression of the force exerted by electromagnetic fields on a volume containing a distribution of electrical charges and currents. If electric and magnetic dipoles also happen to be present in the material medium, they are traditionally treated by expressing the corresponding polarization and magnetization distributions in terms of bound-charge and free-current densities, respectively. In this way, Maxwell's macroscopic equations are reduced to his microscopic equations, and the Lorentz law is expected to provide a precise expression of the electromagnetic force density on material bodies at all points in space and time. He presented theoretical evidence of the incompatibility of the Lorentz law with the fundamental tenets of special relativity. Argued was that the Lorentz law must be abandoned in favor of a more general expression of the electromagnetic force density, such as the one discovered by A. Einstein and J. Laub in 1908. Not only is the Einstein-Laub formula consistent with special relativity, it also solves the long-standing problem of "hidden momentum" in classical electrodynamics. Presented August 24, 2012.

Dr. Pint's experiences so far have been focused around the synthesis and development of nanoscale materials, and their integration into a broad range of applications, but generally focused around energy devices. He currently June 2012) works as a Research Scientist in the Extreme Technology Research group at Intel Labs in Santa Clara, CA, with a research focus on the development of efficient energy devices. Starting in August 2012, he will be an Assistant Professor of Mechanical Engineering at Vanderbilt University with a research thrust designed around using my expertise to develop efficient and integrated energy devices. His professional long-term passion lies in designing and developing disruptive, transformational earth-abundant and cost-effective energy systems and devices that have promise to displace diminishing fossil fuel resources. Presented January 20, 2012.

Dr. Finkelstein is a physics education researcher who studies the role of context in student learning, and conditions that support or inhibit student learning in physics. He conducts research is in physics education, and particularly the role of context in student learning. He is one of the directors of the Physics Education Research group at Colorado, as well as director of Colorado's Integrating STEM Education program, which supports a variety of programs in STEM Education research and reform at Colorado. Noah studies conditions that support students’ interests and abilities in physics, with research projects that range from the specific (how do students use representations or analogies in learning physics?), to the course-scale (the role of computer simulations in learning, or implementation of Tutorials), to the departmental / institutional scale (what models of educational reform are sustainable and scalable? How can universities effectively partner with communities in Informal Science Education.). His theoretical work seeks to build models of learning that emphasize the critical and inextricable role of context in student learning of physics. Presented February 17, 2012.

Dr. Mazumdar's interests are broadly in the area of Materials Physics and Device Engineering. Currently, his projects are focussed on investigating the electronic and structural properties of functional and multiferroic oxide thin films and heterostructures, and on engineering these materials for technological applications. He utilizes a combination of thin film growth techniques such as pulsed laser deposition (PLD) and sputtering; structural, magnetic and physical property characterization (X-Ray diffraction, magnetometry and scanning probe microscopy techniques); micro- and nano-device fabrication and their transport properties; and theoretical investigation of electronic properties using first-principles techniques. Application areas include spintronics, thermoelectrics and photovoltaics. He is the author of over 20 publications. Presented Feb 1, 2012.

Dr. Raman's group investigates macroscopic quantum mechanics using ultralow temperature gases—laser cooled clouds of atoms suspended inside a vacuum chamber at temperatures less than one millionth of a degree above absolute zero. We explore topics ranging from superfluidity in Bose-Einstein condensates (BECs) to quantum antiferromagnetism in a spinor condensate. Our goal is to use advanced atomic experimental techniques to illuminate contemporary phenomena in condensed matter physics, particularly in correlated quantum systems. Apart from fundamental studies, we are seeking to build cutting edge sensors that exploit the quantum properties of ultracold gases. Presented February 10, 2012.

Dr. Rogers studies the solar dynamo. This involves studying the hydrodynamics and magnetohydrodynamics of stellar interiors in general and in particular in the Sun. She uses large scale numerical simulations in two and three dimensions to study the interactions of turbulence, waves and magnetic fields. While mainly focused on the solar interior, Tami is interested in fluid dynamics in general, as applied to stellar and planetary interiors and atmospheres. Presented March 2, 2012.

Larry Winter is the Deputy Director of the National Center for Atmospheric Research (NCAR). In that role he assists with scientific leadership, provides administrative oversight, and helps formulate strategic goals, budgets, and programmatic priorities for the institution. Dr. Winter is also an Adjunct Professor in the Department of Hydrology and Water Resources at the University of Arizona. Before moving to NCAR, Dr. Winter was leader of three groups at Los Alamos National Laboratory. During 1997-1999 he led the Computer Research and Applications Group; from 1995-1997 he led the Geoanalysis Group; from 1990-1995 he led the Applied Mathematics and Statistics Team. Presented March 23, 2012.

Adam Block is most well-known for his abilities to speak and communicate difficult concepts in astronomy in simple and creative ways. Over the past 15+ years he has hosted many thousands of evenings for the public and strives to maintain quality programs that are fresh and exciting with unflagging enthusiasm. Adam is also recognized around the world as a leading astrophotographer. The images he produces as part of public outreach programs are published in magazines, books, posters, and widely on the internet. His images have graced NASA's "Astronomy Picture of the Day" website more than 50 times and have been used as reference images by amateur and professional astronomers alike. Presented March 9, 2012.

Dr. Mativetsky's presentation discussed organic electronics, using materials based on organic molecules as active components in electronic devices. Presented January 27, 2012.

Dr. Enquist's lab investigates how functional constraints at the level of the individual (anatomical and physiological) influence larger scale ecological and evolutionary patterns. He is broadly trained plant ecologist. His lab uses both theoretical, computational, biophysical and physiological approaches to address integrative questions related to (1) the evolution of form and functional diversity; (2) the origin of allometric relationships (how characteristics of organisms change with their size) and the scaling of biological processes - 'from cells to ecosystems'; (3) the evolution of life-history and allocation strategies; and (4) community ecology and macroecology. His research also includes the monitoring of long-term dynamics of growth and change within a tropical forest in the Area de Conservation, Guanacaste, Costa Rica. Presented March 30, 2012.

Dr. Simmmons concludes that the Standard Higgs Model is a low-energy effective theory of electrroweak symmetry breaking that is valid below an energy scale characteristic of the underlying physics. It is a useful tool but may not tell the whole story. Presented April 20, 2012.

The Maruyama group is exploring several topics in nuclear and particle astrophysics. The experiments range from studying properties of neutrinos to a search for dark matter. We are searching for annual modulation signature from dark matter with the DM-Ice experiment, currently running a 17 kg version at the South Pole, with a 250 kg experiment currently being designed. We are also using the IceCube Neutrino Observatory to study fundamental properties of neutrinos using nearby supernovae. With CUORE, we are looking for a process called neutrinoless double beta decay. If such a process is observed, it would mean that neutrinos are their own antiparticles, and may hold the clue to why we live in a Universe of matter, and not antimatter. The experiment is located in the Gran Sasso National Underground Laboratory in Italy. Presented April 13, 2012

Dr. Wang's research interests are ultra-low energy magnetization switching, electron tunneling in ferromagnet/insulator/ferromagnet structures, spin-dependent transport in semiconductors nano-fabrication, and superconductivity. Presented February 8, 2012.

Dr. Eric A Betterton received The 2012 Professor Leon and Pauline Blitzer Award for Excellence in the Teaching of Physics and Related Sciences. Dr. Betterton received the award and presented "Earth-Dust, Cloud-Dust, Storm-Dust: The pervasive Nature of Atmospheric Aerosols in our Lives." The presentation and lecture was held on Tuesday, March 20, 2012. A reception followed in the Steward Observatory Lobby Sponsored by the Departments of Physics and Atmospheric Sciences. Dr. Betterton's research focuses on atmospheric and environmental chemistry. This work includes urban air quality, ground water remediation, frozen solution chemistry, water isotopic chemistry, cloud condensation nuclei, and microphysical and chemical properties of winter precipitation.

Dr. Blum studies study Quantum Chromodynamics (QCD), the fundamental theory of the strong force. This force binds quarks and gluons together to form protons and neutrons, the fundamental building blocks of matter that make up our world. In principle, QCD describes all of nuclear physics, in the sense that Quantum Electrodynamics describes solid state physics. It is also important to particle physics because most of the particles detected in high-energy collider experiments like those at Fermilab's Tevatron and the soon to be complete Large Hadron Collider at CERN are hadrons, the bound states of quarks and gluons. His lecture was given on September 16, 2011.

Dr. Burke is Professor, Heretical Physical and Computational Chemistry, in UC-Irvine's School of Physical Sciences. His research interests include theoretical chemistry, theoretical physics, math, and computation. His lecture was given on September 2, 2011.

Dr. Jokipii’s research concerns many areas primarily related to plasmas and the transport and acceleration of cosmic rays and energetic particles in the solar wind and in the galaxy. Major current thrusts revolve around work on the Voyager and ACE space missions, for which he and his group are guest investigators, specializing in theoretical interpretaion and modeling of the observations. Specifically, Dr. Jokipii’s group is currently in the midst of an extensive program of theoretical research into shock waves in turbulent astrophysical plasmas. This involves extensive theoretical work and three-dimensional simulations, which are exceedingly demanding of computer resources. His lecture was given on October 29, 2010.

Dr. LeRoy's research interest is using scanning probe microscopy to study interactions in nanostructures. By combining electrical transport measurements with the spatial information from scanning probe microscopy we can gain new insight into the behavior of electrons inside nanostructures. Currently we are investigating interaction effects inside carbon nanotubes using scanning tunneling microscopy. The 1D nature of nanotubes means that Coulomb interactions are very important, leading to effects such as Luttinger Liquid behavior and the Kondo effect. We are also developing new scanning probe microscopy techniques to image electron wavefunctions inside semiconductor quantum dots. This will allow the study of effects such as electron-electron interactions and coherence in these systems. His lecture was given on September 23, 2011.

Axions are particles associated with the Peccei-Quinn mechanism for solving the strong CP problem. They are also interesting candidates for the dark matter. axions with very large decay constant f, say around the GUT scale. Such axions only make sense in an inflationary universe, and then only by having extremely small misalignment between the axion field in the early universe, and the value preferred by QCD. This fine-tuning can be explained invoking the anthropic principle --- it is actually the only case I know of where the anthropic principle really makes sense: one knows the a priori distribution of initial axion field values (a/f being a random angle), and one knows that a Universe without a particularly small range of values for a/f would not support habitable galaxies. With inflation all initial values for a/f occur somewhere, and we live in the only part of the Universe where we could live: where the galaxies are! In my paper with Ann we discuss how there might be observable consequences in this scenario (if we are lucky): the fine tuning of a/f makes us extremely sensitive to spatial variations in a/f, and it turns out the existence of a cosmic axion string as much as 1,000,000 time farther away than our cosmic horizon could be seen as a difference between our peculiar velocities relative to the CMB, and relative to distant type I supernovas. Seeing this effect would be a stunning window into the pre-inflationary Universe! His lecture was given on November 4, 2011.

Ryan Gutenkunst received his Ph.D. in physics from Cornell University, where he worked with Jim Sethna on unveiling universal “sloppy” parameter sensitivities in systems biology models and on modeling their evolutionary implications. He then did a postdoc with Carlos Bustamante, where he developed ∂a∂i, a powerful method for inferring population histories from genomic data. His second postdoc was with Byron Goldstein at Los Alamos National Lab, where Ryan modeled aspects of immune signaling in mast cells. Ryan joined the faculty in Molecular and Cellular Biology at the University of Arizona in Fall 2010. He is also a member of the BIO5 Institute, the Department of Ecology and Evolutionary Biology, the Program in Applied Mathematics, and the Program in Genetics. He continues to work on both systems biology and population genetics, with a focus on understanding the evolution of biomolecular networks. His lecture was given on October 7, 2011.

James P. Vary is Professor of Physics and Past Director of the International Institute of Theoretical and Applied Physics (IITAP) at Iowa State University (ISU). He graduated from Boston College (B.S., 1965, Magna Cum Laude), and Yale University (M.S. ,1966 and Ph.D., 1970). He spent two postdoctoral years at MIT's Center for Theoretical Physics and three years at Brookhaven National Laboratory as Assistant then Associate Physicist. In 1975, he joined the faculty at Iowa State University and has fostered the development of a 10-member high-energy nuclear theory group. Professor Vary's research activities span strong interaction physics from ab-initio nuclear structure theory to include fundamental tests of nature's symmetries and to nuclear applications of Quantum Chromodynamics (QCD). Computational physics is another major area of emphasis. His lecture was given on November 18, 2011.