The projects and groups listed below are intended to provide interested students with an overview of research offerings in the Department of Physics, University of Washington. The list is not inclusive, but it is representative of the breadth of research opportunities within the Physics Department and INT. Students with particular interests should feel free to ask Wick (haxton@phys.washington.edu) or Jerry (seidler@phys.washington.edu) whether special projects can be designed-we have done this in past years with good success.
Nuclear Physics Experiment
Weak Interactions, Symmetries, and Neutrinos
In addition to SNO (see below), our group is involved in a number of projects probing the weak interaction and neutrino properties. Current projects underway include emiT, a precision neutron beta decay measurement that is testing time-reversal invariance, as well as SAGE, the Russian American Gallium Experiment. On SAGE we are involved in the analysis of data from this gallium based solar neutrino experiment (an experiment sensitive to the low-energy p-p fusion neutrinos). We are also participating in new experiments. One, called KATRIN, will attempt to make a direct measurement of the neutrino mass via tritium beta decay. Two other experiments, MOON and Majorana, will use double beta decay to attempt an indirect, but very sensitive measurement of the neutrino mass. Most of our experiments have to be performed underground to escape the cosmic ray backgrounds. To this end we are actively participating in the establishment of a National Underground Science Laboratory (NUSL). An REU student is encouraged to consider working with us in any of these areas. More details of all these research are available at: http://ewiserver.npl.washington.edu/
Testing the Equivalence Principle using a High-Precision Torsion Balance
The Eot-Wash group is building a new instrument to make the world's most precise test of Einstein's equivalence principle which says that gravitation is equivalent to an acceleration of the coordinate frame and is the underpinning of general relativity. The measurements may also indicate the presence of new scalar fields associated with the dark energy in the universe. You can find out more about this by clicking on the Eot-Wash research group on the University of Washington Physics Department home page on the Web. We have several interesting technical projects suitable for experimentally inclined summer students. Our lab is well equipped with instrumentation, machine and electronic shops so that plenty of resources are available for attacking these problems. Some examples are:
Fundamental Physics with Ultra-Cold Neutrons
We are carrying out development work on an experiment to measure the beta asymmetry in the decay of polarized Ultra-Cold Neutrons (UCN). UCN are neutrons with velocities so low ( a few m/s) that they can be physically bottled and thus one can produce a compact source of neutrons to study neutron beta decay. We have constructed a prototype source at the Los Alamos Neutron Science Center (LANSCE) that is the most intense UCN source in the world. The UCN are produced from spallation neutrons made with the 800 MeV LANSCE accelerator that are moderated into the UCN regime using solid deuterium at 5 K. Research activities directed towards the beta asymmetry experiment involve design, construction, and testing of systems with the prototype UCN source, data acquisition and analysis, detector development, Monte Carlo simulations, and studies of systematic effects. We believe that a mix of some of these activities would provide a very good and broad learning experience for a REU student. The research would be carried out at Los Alamos National Laboratory, located in the mountains of northern New Mexico close to Santa Fe.
Gravitation Experiment
Sub-millimeter-scale Tests of the Gravitational Inverse-square Law and Other Precision Tests of Gravitational Physics
The Eot-Wash group is pursuing a new project to test an exciting prediction that Newton's inverse-square law could break down at the millimeter scale. If verified experimentally, this prediction would provide strong evidence for more than 3+1 dimensions, i.e. that some of the "extra dimensions" of modern theories could have detectable consequences. Our experiment employs a novel torsion balance and a rotating attractor. Three REU students from the programs of the past two years worked on the first version of this experiment which has just appeared in Physical Review Letters. New projects will include helping to construct a clean room for the experiment and testing an "electrostatic torsion fiber stiffener" that may increase the resonant frequency of the torsion fiber without increasing the fiber noise. We are also making torsion balance measurements with a spin polarized test body to test CPT symmetry and to search for new spin-coupled forces. REU projects associated with testing the magnetic properties of matter will be available. Our lab is well equipped with instrumentation, machine and electronic shops so that plenty of resources are available for attacking these problems. You can learn more about our group by clicking on the Eot-Wash research group on the University of Washington Physics Department home page.
New method to test the 1/r2-law of gravity
In the past two years our group has developed a method to test gravity at distances much smaller than a millimeter. Any deviation from Newton's 1/r2-law of gravity would imply that there are more than 3 spatial dimensions in nature. String theories, which describe a path towards grand unification, have many extra dimensions. We are now investigating a conceptually new torsion balance system, which might yield a substantial improvement over our previous setups. The REU project will be a feasibility study of this new method. This project will introduce you to many experimental techniques developed in this lab.
Particle Astrophysics Experiment
The Sudbury Neutrino Observatory
The Sudbury Neutrino Observatory (SNO) is a massive, heavy water Cerenkov detector in operation 2 km underground in Sudbury, Ontario. SNO's primary mission is the study of solar neutrinos, It is also measuring atmospheric neutrinos, and it is constantly monitoring for neutrinos emitted from nearby (galactic) supernovae. Using its unique ability to distinguish between neutrino flavors, SNO, in conjunction with the Super-Kamiokande detector, has provided the definitive resolution of the long standing "solar neutrino problem," where all existing experiments observe fewer neutrinos from the sun than predicted by theory. We now know that neutrinos have mass and oscillate between flavors. Work at UW in the summer of 2002 by our group (4 Faculty, 2 postdoctoral fellow, 8 graduate students) will concentrate on analysis of the data being collected to further refine our understanding of neutrino properties. In addition we are making final preparations to upgrade the neutron detector system that will be used by SNO to make the key measurement of neutral-current neutrino interactions. There are numerous interesting hardware, software, and data analysis research opportunities available. More information on SNO, plus other useful links, can be found at our web site:
http://EWIServer.npl.washington.edu/sno/sno.html
WALTA
WALTA (Washington Large Area Time coincidence Array) is a project to investigate the highest energy cosmic rays with the participation of middle and high school students and teachers throughout the Seattle area. Particle detectors and front-end electronics are sited at high schools and linked to UW via the schools' Internet connections. The school network forms an extensive air shower (EAS) array suitable for detection of extremely high energy cosmic ray showers. Eleven schools are already participating, and during Summer, 2002, we will hold a workshop to train teachers from another set of ~10 schools. REU students will assist with detector development and installation, preparation of materials for the summer workshop and classroom use, and maintaining contact with teachers and students.
Condensed Matter Experiment
Dynamics at Ice Surfaces
The environment of molecules of a given material near an interface is different from that of molecules in the bulk of the material, due to bonds missing at the interface. Thus the structure and dynamics near an interface can be quite different than in the bulk. Water ice is important in a number of environments on the earth, in the atmosphere, on comets and planetary satellites, and in space. Atomic resolution non-contact mode AFM measurements to investigate the structure, morphology, and annealing behavior of ice that is vapor deposited on various single crystal substrates in ultra-high vacuum work for temperatures between 50K and 150K using a new microscope manufactured by Omicron in Germany as well as a homemade low-current low-energy electron diffraction apparatus. The fundamental information obtained by such measurements will aid in understanding the influence of substrate on the growth and annealing behavior of ice at low temperatures such as occurs in the much colder environments in space where comets and dark interstellar media occur. An undergraduate student could assist in these experiments, learning about ice surfaces as well as about the surface physics techniques used. For more information see http://faculty.washington.edu/fain/research.html.
Linear and Nonlinear Elasticity of Foams
Elastic foams are very interesting from both an applications and a theory
viewpoint. One long-standing problem has been a disconnection between
simulation, theory, and application. The best simulations
predict the elasticity at very small strains, the most reliable theory
ignores the real disorder in the materials, and the
industrially-interesting regime is often at high strains where neither the
simulations nor the theory applies. In this project, we will build a new
apparatus to directly measure the stress-strain relationship for polymer
foams over five decades in strain, spanning the low-load linear
regime to the initial onset of non-linear elasticity. This data will
allow a critical test of the reliability of existing simulations and
theory.
Wavelet Analysis of Inhomogeneous Materials
Although the comprehensive understanding of crystalline materials stands as one of the cornerstones of modern physics, the theoretical and commercial importance of nanoscale-amorphous or microscale-inhomogeneous should not be overlooked. Granular matter, foams, and paper are central in more than 20% of the GNP of the United States and are also materials of ongoing research interest in condensed matter physics. My group has recently developed an apparatus for micron-resolution studies of these materials in 3-dimensions. We have used this apparatus to perform the first precise experimental work on 3-D structure of granular matter in almost 50 years, the first 3-D studies of many classes of solid foams, and the first truly fiber-level studies of the 3-D structure of paper. The question is: How do you capture the important statistical aspects of a structure with only short-range order? In this project, we'll investigate the use of wavelet analysis and other tailored orthogonal-polynomial decompositions to address this question. Strong math skills and some programming knowledge are desirable for students interested in this project, although no prior knowledge of wavelets analysis is necessary.
Research in Physics of Music
Physics of Music investigates the production, propagation and perception of musical sound. Current projects at UW include room acoustics studies using modern "minimally intrusive" techniques, physics of consonance/dissonance (including a project using real-time MIDI control to achieve context-dependent tuning), experiments on absolute pitch perception, and measurement and evaluation of pipe organ sound, with emphasis on the role of physical imperfections necessary to achieve the perception of perfection. The lab is equipped with advanced hardware and software, including the CLIO system based on the Maximum Length Sequence method (used in many 'spread-spectrum' applications). Recently, we added LabVIEW data acquisition hardware and software. In addition to Physics, these projects touch on Computer Science, Electrical and Mechanical Engineering, Hearing Research, and of course Music. Many aspects of this research are well suited for the participation of undergraduate students, especially those with strong computing skills (both in programming languages as well as with hardware/networking experience.)
Atomic Physics Experiment
Atomic Tests of Parity Nonconservation and Time Reversal Symmetry
Students will be able to work directly on small scale atomic physics experiments that probe the elementary particle physics frontier. In one type of experiment, the electroweak force between electrons and quarks inside atoms is measured by the small degree of left-right asymmetry displayed by these atoms. In another type, a permanent electric dipole of an atom is being looked for as evidence of forces that distinguish between forward and backward in time. Other experiments include laser trapping of Yb atoms and applications of atomic magnetometers to biological measurements. In these experiments students can use and develop high precision lasers, ion traps, laser cooling techniques, and other tools of modern atomic physics.
Precision Measurements on Single Trapped, Laser-Cooled Ions
Our experimental work involves trapping single atomic ions in an ultra-high vacuum and bringing them essentially to rest using the radiation pressure from laser beams ("laser cooling"). Our motivation is to observe simple atomic systems in nearly complete isolation, which will ultimately enable us to make a single-ion atomic clock which is accurate to about one second in the lifetime of the universe. Interested REU students can help our efforts by constructing simple electronic or mechanical devices which will be used in the experiments.
Particle Physics Experiment
Studies of the performance of planned gamma ray telescope
We at the UW have the lead in performing simulations of the response of GLAST, a gamma ray detector to be launched in low-earth orbit in early 2006, to incoming particles. We are involved in planning and executing such simulations, modeling a variety of sources of particles, some representing noise, and some the sort of signals we hope to study, like gamma ray bursts. There are several projects that a student could contribute to; they would involve some programming experience in C or C++. (We actually use C++.)
Physics Education Research
Research-based Instructional Strategies for Teaching Physics
The Physics Education Group conducts research on student understanding of physics and uses the results to guide the design of instructional materials, which are intended for national distribution. The effectiveness of these curricula is assessed at the University of Washington and at many other institutions. REU students will have the opportunity to participate in programs shaped by the group's research, such as the summer program for K-12 teachers and the tutorials for the introductory physics course. In addition to taking part in classroom activities, previous REU participants assisted in investigations of the effect of different instructional strategies on student understanding of important fundamental concepts by analyzing student performance on qualitative questions before and after instruction.
Computational Astrophysics
Planetesimal Dynamics
From planet formation to planetary rings, from fragile comets and asteroids to sandpiles, there is a large diversity of problems related to planetary science that can be addressed with numerical simulations. For example, the surprising configurations of planetary systems recently discovered around nearby stars imply that planets can undergo large-scale radial motions during their formation. It is known that planetesimal scattering can cause a planet's orbit to shrink and circularize, but numerical simulations are needed to quantify this process for various disk parameters. As a different example, the spectacular breakup of Comet Shoemaker-Levy 9 and measurements of remarkably low bulk densities in some asteroids imply that small bodies in our Solar System may not be solid monoliths as we once thought. Numerical simulations reveal how these fragile bodies evolve but there are many parameters to explore. At even smaller scales, there are interesting topics in granular dynamics to investigate, such as self-organized criticality in sandpiles. The chosen project would provide experience performing simulations with sophisticated numerical code on a cluster of workstations and carrying out some analysis and visualization. We invite one REU student to join us in this effort. For more information, visit www-hpcc.astro.washington.edu or email trq@astro.washington.edu.
Condensed Matter Theory
Building Simulated Materials by Cellular Automata
In computational statistical physics, a key question is often: Does nature specify equations or algorithms? The realistic simulation of real disordered materials (such as foams, powders, and a range of hard and soft biological tissues) pose unique technical problems related to this question. Foremost among these problems is the difficulty of creating an ensemble of simulated materials with the same structural correlation functions as a class of real material. Unfortunately, many methods for generation of simulated disordered materials are known to be either statistically unfounded or only weakly relevant to real materials of interest. In this project we will review the prior methods for generating simulated disordered materials, and then investigate several new ideas based on Bayesian statistics and efficient computation by cellular automata. This project is a good fit for students with a good computing skills and a strong interest in stochastic processes, simulations, or nonlinear physics.
Parallel Calculations of Electronic Structure and Response Functions
This project deals with calculations of electronic response functions,
such as the absorption and emission of x-rays, based on parallel
computational algorithms. Our codes are based on a real space
Green's function (RSGF) formalism which is applicable to nano-scale
systems of order 103 atoms.
Nuclear and Particle Theory
Effective Field Theory in Nuclear Physics
Effective field theories (EFTs) are based on the simple idea that details of the short-distance interactions of a system of particles should not strongly affect the long-distance (low-energy) properties of that system. They allow one to include information about the interactions between the particles at short range, while making only minimal assumptions about the short-range dynamics. Hence, EFTs have proven extremely useful in exploring the ways in which effects not included in the "standard model" of particle physics might manifest themselves in low-energy observables. In recent years much effort has been invested in applying these ideas in nuclear physics. We know that the forces between neutrons and protons are very complicated at short distances, and yet we believe that these complications should be irrelevant for many nuclear physics phenomena. Because of the complicated strong interactions which are inherent to nuclear physics, constructing EFTs in nuclear physics poses formidable theoretical challenges. This REU project offers an exciting opportunity for an undergraduate student to become involved in frontier research in nuclear physics which involves nuclear theory, quantum mechanics and quantum field theory.
Light Front Quantum Mechanics
In 1947 Dirac introduced a new form of relativistic quantum mechanics in which the variable ct +z acts as a "time" coordinate and ct-z acts as a "space" coordinate. This so-called light front formalism was largely forgotten until the 1970's, when it turned out to be useful in analyzing a variety of high energy experiments. Despite the phenomenological success of this formalism, it has enjoyed only limited use in computing wave functions of particles and atomic nuclei. The present project is devoted to using the light front formalism to solve quantum mechanics problems involving bound and scattering states. A mathematically strong REU student would learn about relativistic quantum mechanics through the process of solving the relevant relativistic equations. This project would involve working on interesting and timely topics and could provide great preparation for graduate school quantum mechanics, field theory or even string theory.
Faculty: Peter Doe, Steve Elliott, Hamish Robertson, and John Wilkerson
Faculty: Eric Adelberger, Jens Gundlach, Blayne Heckel
1) developing a secondary torsion balance to monitor the stability of gravity gradients in the lab.
2) measuring vibration noise levels and developing vibration isolation methods to reduce the noise.
3) testing the noise performance of torsion fibers made of different materials.
Faculty: Thomas Bowles
** This project is sited in New Mexico **
Faculty: Eric Adelberger, Blayne Heckel, and Jens Gundlach
Faculty: Jens Gundlach and Eot-Wash group
Faculty: Peter Doe, Steve Elliott, Hamish Robertson, and John Wilkerson
Faculty: R. J. Wilkes, T. H. Burnett
Faculty: Sam Fain
Faculty: Jerry Seidler
Faculty: Jerry Seidler
Faculty: Vladi Chaloupka
Faculty: Norval Fortson, Blayne Heckel
Faculty: Warren Nagourney
Faculty: Prof. Toby Burnett
Faculty: Lillian C. McDermott, Paula Heron, Peter Shaffer
Faculty: Tom Quinn
Faculty: Jerry Seidler
Faculty: John J. Rehr, AL Ankudinov
Silas Beane
Faculty: Jerry Miller