College of Arts and Sciences

Neutrino mass and mixing are amongst the major discoveries of recent years. From the observation of neutrino flavor change in solar and atmospheric neutrino experiments to the measurements of neutrino mixing with terrestrial neutrinos, recent experiments have revealed new particle properties of neutrinos and provided the first hint of physics beyond the Standard Model of particle physics. These observations have helped solve the long-standing Solar Neutrino Problem, the apparent deficit of the observed electron solar neutrino flux, and have contributed to a better understanding of the role of neutrinos in the Universe. A broad field of neutrino research has emerged in particle,

Continue reading… Recent Discoveries in Neutrino Physics – Karsten Heeger

Magnets utilizing organic groups with essential spin have been reported since the mid-1980s. Though initial organic-based magnets (OBMs) had magnetic ordering temperatures (Tc’s) below 5K, OBMs now have Tc’s up to 400K. The chemical control of OBMs will be introduced. In addition to magnetic phenomena already known for conventional transition metal and rare earth magnets, OBMs feature unique phenomena enabled by the shape and internal electronic structure of the organic molecules. Examples are illustrated with experimental results for magnets based on tetracyanethylene, [TCNE], which as an anion has spin ¸. For example, application of blue light to Mn++[TCNE]-2 increases the magnetic susceptibility below the Tc of 75 K and green light reverses the effect.

Continue reading… Organic-Based Magnets: New Materials, New Phenomena, And New Applications – Art Epstein

The Paradigms in Physics Program at Oregon State University has totally reformed the entire upper-division curriculum for physics and engineering physics majors. This has involved both a rearrangement of content to better reflect the way professional physicists think about the field and also the use of a number of reform pedagogies which place responsibility for learning more firmly in the hands of the students. Along the way we are learning about what it takes to successfully design and implement large scale modifications in curriculum and to institutionalize and disseminate them. The particular emphasis will be on how our reforms have influenced how we teach quantum mechanics.

Continue reading… Revitalizing the Upper-Division Physics Curriculum – Corinne Manogue

Many macromolecules like proteins and polypeptides are known to form secondary structures called a-helices at low enough temperatures or under appropriate solvent conditions. The transition from the ordered state (a-helix) at low temperatures to the disordered one (random coil) at high temperatures is called the helix-coil transition. Simulating this transition and the resulting physical behavior of a-helices has proven to be a very challenging task even for modern computational systems. In this talk I will present a novel geometric approach to the simulation of the helix-coil transition in worm-like polymers. This approach combines the traditional statistical-mechanical concepts proposed by Zimm,

Continue reading… Helix-Coil Transition of Worm-like Polymers – Gustavo Carri

Despite our best and most sincere efforts, there is an alarming disconnect between what we teach and what students learn and understand. The goal of physics education research is to help close this gap. I will discuss, using my own research and activities as examples, the three major components of physics education research: (1) Identification of student difficulties, (2) curriculum/pedagogy development to minimize the sources of these difficulties, and (3) implementation/evaluation of new pedagogy and teaching methods. My own research has emphasized student understanding of basic (energy/momentum) and advanced (quantum mechanics) concepts, and has strived to find common origins for the ways in which misconceptions arise.

Continue reading… Physics Education Research: Closing the gap between what we teach and what is learned – Chandralekha Singh

Recently discovered algorithms indicate that quantum computers may one day enable exponentially faster computation than is fundamentally possible using their classical counterparts. The realization of this promise hinges above all on the ability to protect quantum computers against the deleterious effect of the interaction with their environment, leading to decoherence. A decohered quantum computer is equivalent to a badly malfunctioning classical computer. In this talk the what’s, why’s, how’s and problems of quantum computation will first be briefly reviewed. This will be followed by a proposal for a solution of the decoherence problem, with applications to atomic and solid-state quantum computing.

Continue reading… Quantum Computers and Decoherence: Exorcising the Demon from the Machine – Daniel Lider

In statistical mechanics, the term “quenched disorder” refers to heterogeneity that is fixed, unable to respond to changes in a material. Thermal fluctuations and quenched disorder are two distinct types of randomness that can control the statistical mechanics of condensed matter. In soft materials, thermal fluctuations usually dominate because heterogeneities are free to move around a sample. However, recent research has found certain types of soft materials where quenched disorder plays the dominant role. In this talk, we present theoretical models for two such systems. For helical polymers, including polyisocyanates and DNA, we show that the helical order of the chains is controlled by the disordered sequence of monomer units.

Continue reading… Quenched Disorder in Soft Materials: Helical Polymers and Liquid-Crystalline Elastomers – Jonathan Selinger

One approach to solving the problem of quantum gravity is based on the causal set hypotheis, which states that the deep, quantum structure of spacetime is discrete and is what is known in mathematics as a “partial order” or “poset”, a kind of extended family tree. Causal set theory has now reached a stage at which questions of phenomenology are beginning to be addressed. this talk will introduce the basic concepts and motivations behind the hypothesis and address some of the latest developments which include: (i) an apparently confirmed order of magnitude prediction for the cosmological constant, the only prediction made in any propsed theory of quantum gravity that has been subsequently verified by observation (ii) a classical stochastic causal set dynamics which arguably is the most general consistent with the discrete analogs of general covariance and classical casuality (iii) a rigorous characterization of the observables (or “physical quetions”) of causal set cosmology,at least in the classical case.

Continue reading… Causal sets as the deep structure of spacetime – Fay Dowker

Vast progress in theoretical solid state physics has been made by constructing models which mimic the low-energy properties of solids. Essential to the success of this program is the separability of the high and low energy degrees of freedom. While it is hoped that a high energy reduction can be made to solve the problem of high temperature superconductivity in the copper oxide materials, I will show that no consistent theory is possible if the high energy scale is removed. At the heart of the problem is the mixing of all energy scales (that is, UV-IR mixing) in the copper-oxide materials.

Continue reading… The Full Mottness: Asymptotic Slavery – Philip Phillips

Recent experiments have confirmed that the universe is expanding at an ever-increasing rate, driven by a presently unknown form of “dark energy.” To determine what the dark energy is as opposed to that it is will require a new generation of experiments of unprecedented precision. An international team of scientists is now planning for a SuperNova /Acceleration Probe (SNAP), a new type of space telescope with a wide field optical-to-near-infrared imager and spectrograph. SNAP will observe thousands of supernovae over a wide range of redshifts to measure the expansion history of the universe. By examining how the equation of state of the universe evolves over cosmological time,

Continue reading… Shedding Light on Dark Energy with SNAP – Gregory Tarle

Continue reading… Physics Tricks for Fun and Profit: a Physicist’s Adventures in Theoretical Ecology – Robin Snyder

Last summer, the Tevatron experiments released the first physics results based on the substantial quantity of data collected so far in Run II. I will give an overview of the broad physics program that will be accessible with the expected Run II dataset that is 20-100 times larger than what we have now. This will include recent results and future projections for our studies of the origin of mass (the Higgs boson?), the discovery of new forms of matter (Dark Matter? Supersymmetry?), and the potential explorations of new large extra space-time dimensions, if they exist.

Continue reading… The D0 Experiment at the Fermilab Tevatron: Recent Results and Prospects – Mike Hildreth

Amyloid fibrils are filamentous structures with remarkably similar morphologies formed by a variety of polypeptides with remarkably dissimilar amino acid sequences. We are using novel nuclear magnetic resonance (NMR) techniques to investigate the molecular structures of amyloid fibrils, especially amyloid fibrils that deposit in the brains of Alzheimer’s disease patients. Physics plays two roles in this highly interdisciplinary work: (1) fundamental physical issues, such as the nature of interactions that stabilize amyloid fibrils, are unresolved and motivate our measurements; (2) the NMR techniques themselves involve interesting physical principles and phenomena. Our most recent progress will be described, with an emphasis on the physical science aspects.

Continue reading… Structural Studies of Alzheimer’s Amyloid Fibrils by NMR: Where’s the Physics? – Rob Tycko

Cosmic inflation claims to make the initial conditions of the standard big bang “generic”. But Boltzmann taught us that the arrow of time arises from very non-generic (“low entropy”) initial conditions. I discuss how to reconcile these perspectives. The resulting insights give an interesting way to understand and compare inflation and other ideas that purport to offer alternatives to inflation.

Continue reading… Cosmic Inflation and the Arrow of Time – Andreas Albrecht

QCD allows us — indeed, invites us — to address some basic questions from a new perspective, and with much greater precision than was possible before. These include the origin of mass, the feebleness of gravity, the `specialness’ of the parameters required to support life (anthropic principle), the nature of fundamental versus effective theories, and the computability of physical laws. I’ll describe the insights that QCD affords into these issues.

Continue reading… QCD and Natural Philosophy – Frank Wilczek

The visible world could lie on a membrane floating in higher-dimensional space. The extra dimensions would explain the weakness of gravity and the origin of the minuscule “dark” energy in the Universe. If so, the new dimensions, black holes, quantum gravity and string theory may become experimentally accessible in this decade.

Continue reading… The Universe’s Unseen Dimensions – Gia Dvali

Magnetic Resonance Imaging (MRI) is the most novel and important medical imaging modality since the advent of the X-ray. MRI grew out of the long development by physicists of atomic spectroscopy, atomic and molecular beam resonance and, finally, nuclear magnetic resonance (NMR) in condensed matter. The operation and economics of MRI systems depend critically on the performance of magnets, pulsed magnetic field gradient windings and rf coils, and necessity has spurred development of much science and innovative technology in these areas. Superconducting magnets have come to be the magnet of choice because of their ability to produce strong, stable, homogeneous magnetic fields (0.5 T to 8 T) in large enough volumes to accommodate human subjects.

Continue reading… Magnetic Resonance Imaging: Applied Physics and Electromagnetics – William A. Edelstein

The detection of extrasolar planets is one of the great scientific discoveries of the past decade. Most of these planets planets move on orbits with substantial eccentricities. The origin of these large eccentricities is an unsolved puzzle. We propose that they result from the exchange of angular momentum and energy between the planets and the disks from which they form. These interactions are concentrated at discrete Lindblad and corotation resonances. We describe the physics of these resonances and their effects on the planets migration and eccentricity evolution. If both resonances are fully active, the rate of eccentricity damping by corotation resonances is slightly larger than its excitation rate by Lindblad resonances and the eccentricity decays.

Continue reading… Exciting the Eccentricity of Extrasolar Planets – Re’em Sari

In the last few decades, x-ray physics has made tremendous advances, and the development is expected to accelerate with the advent of x-ray free-electron lasers (XFEL). An XFEL will emit transversely fully coherent x-ray pulses of ca. 100fs duration at a peak power of 1010W . The LCLS project at Stanford and TESLA at DESY, Hamburg are in the advanced stages of planning and scientific cases were developed. A few examples from the fields of nonlinear optics, quantum optics, and the study of ultrafast phenomena will be presented in the talk and results from some experiments in these fields that have recently been done at synchrotron radiation facilities will also be mentioned.

Continue reading… Nonlinear Optics, Quantum Optics and Ultrafast Phenomena with X-Rays from Synchrotrons and Free-Electron Lasers – Bernhard Adams

Nanotechnology, once a wonderful dream, is now becoming a reality. In order to selectively modify and construct nanodevices we have to understand how materials transform from one form to another on a nanoscale. Short-pulsed lasers and optical spectroscopic techniques serve as a unique set of tools and methods to initiate and control phase transformations and to study their dynamics on the appropriate time-scale. In my presentation I will review our recent results on the laser-induced phase transformations and outline the current trends of spectroscopic techniques for their diagnostics.

Continue reading… Laser-induced phase transformations on a nanoscale – Vladislav Yakovlev

Consistent formulations of string theory require the existence of additional spatial dimensions. These extra dimensions can play a crucial role in determining the properties of our Universe, shedding new light on some of the greatest mysteries of nature, such as the observed weakness of gravity. If the extra dimensions are as large as the current observational limit at a sub-millimeter scale, they lead to an exciting possibility of testing string theory in the near-future collider experiments and in cosmology. I will discuss how such models emerge from string theory, showing why they are plausible and what are their experimental consequences and predictions.

Continue reading… New Physics and Cosmology from Extra Dimensions – Nemanja Kaloper

We discuss the physics and mathematics of sphere packing and minimal surfaces and use these to explain the crystal symmetries found in macromolecular, supramolecular micellar materials and charged colloids. In the case of molecular assemblies, we argue that the packing entropy of the hard micellar cores is frustrated by the entropic interaction of their brush-like coronas. The observed crystal structures correspond to the Kelvin and Weaire-Phelan minimal foams. We show that these structures are stable for reasonable areal entropy densities.

Continue reading… What’s Kelvin’s Problem? – Randall D. Kamien

Spintronics is an emerging field aimed at using the electron’s spin instead of its charge for information processing and computation. This talk will describe how basic research in this field employs beams of light that behave analogously to conventional electrodes. We will provide an overview of recent fast optical experiments that reveal how the electron’s spin memory in semiconductors is influenced by electrical doping, spatial motion, interfaces, and hyperfine interactions. In the latter case, electron spins not only serve as a magnetometer of local nuclear fields, but can also be used to induce NMR with near-visible light rather than conventional radio-frequency fields.

Continue reading… Getting a Handle on Spintronics with Optical Spin Electrodes – Jay Kikkawa

The Fermilab Tevatron collides protons with antiprotons to create luminosity at a center of mass energy of 1.96 Tev. This talk will start with a description of the steps performed as protons and antiprotons make their way through the chain of Fermilab accelerators before reaching the Tevatron. The rest of the talk will focus on the Tevatron, the factors that determine the luminosity, and some of the fundamental limitations of creating luminosity.

Continue reading… Luminosity in the Fermilab Tevatron – Mike Martens