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Graduate Research Projects


Accelerator-based High Energy Particle Physics

We study elementary particles at very high energies with the Compact Muon Solenoid detector (CMS) at the Large Hadron Collider (LHC) of CERN in Geneva, Switzerland, and from the electron-positron collider at the Stanford Accelerator Center (SLAC), Stanford, California, to address questions such as:

... and many more.

Our group consists of 1 faculty, 2 post docs, 3 graduate students with research participation of undergraduate students.

The Large Hadron Collider at CERN started operation in Fall 2009. From proton-proton collisions at very high energies (several TeV) we want to learn about the existence of new particles that might change our picture of physics profoundly. Many new results will be obtained already within the first year. The BaBar experiment at SLAC collected an unprecedented amount of data and we are finding new particles every year.

Students in our group analyze data from the LHC to reconstruct certain particle processes that potentially produce the so called Higgs boson that might be responsible to generate mass for particles, and B mesons that can help to understand the matter-anti-matter asymmetry of the Universe, or look for completely unknown particles and their signatures. Computers are the main tool for the analyses. Graduate students learn about and apply different particle detection techniques and statistical analysis methods developing smart algorithms.

Our group participates in the commissioning and operation of the silicon pixel detector that has an unprecedented amount of individual readout channels (about 66 million). Most of the data processing occurs right at the detector near the collision point. The new technique and he extreme conditions require many systematic studies to get the instrument operational at its best.

Here at the University we have a detector research laboratory. We study, build and install a pixel detector that is based on diamonds. Pursuing a PhD in our group gives the opportunity to be part of diamond detector research, detector installation and commissioning at CERN and to perform data analysis with high performance computers. We plan to install the largest Diamond pixel detector ever built by the end of 2010 in the CMS detector. It will measure the overall proton-proton interaction rate which is fundamental input for many measurements with CMS.

Please visit us on the Web: http://hep.phys.utk.edu

Contact: Prof. Stefan M. Spanier, spanier@utk.edu or telephone: (865) 974-0597.


Accelerator Physics and Technology at the SNS

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is the world's most powerful accelerator-based neutron scattering facility. The SNS accelerator combines the world's first superconducting proton linac with a record-breaking high intensity proton accumulator ring, resulting in tremendous research opportunities in the field of accelerator physics. The accelerator physics group is seeking qualified graduate students interested in doing research in the following areas:

The research program offers hardware oriented, hands-on research opportunities, and computational and theoretical opportunities. All research avenues involve designing and executing experiments with the SNS high intensity proton beam. More information can be found at http://neutrons.ornl.gov/.

Interested candidates should contact one of the following UT adjunct faculty:


Cellular Biophysics

Cellular biophysics studies organization and molecular processes in living cells. While living cells are very complex entities our understanding of these building blocks of life has become increasingly quantitative over the years. Thanks to this trend cellular biophysics has become an exciting research area for physicists from various backgrounds. In one hand physics based novel experimental methods and tools have potential to tremendously advance research in this discipline. This includes novel implementations of lab-on-chip platform, imaging techniques and quantitative image analysis methods, which we actively develop. On the other hand, physics based models and theories are making big advances in describing inner workings of cells. This applies in particular to the simplest organisms, the bacteria, which we study. Can we understand these simple cells from the basic principles of physics similar to the level of details we understand the organization and behavior of atoms in one day? In approaching this ultimate goal, we carry out quantitative studies of self-organizing processes related to cell division proteins, DNA and bacterial cell wall. Specifically, we seek answers to the following questions: How bacterial cells position cell division proteins? How is bacterial DNA organized and what role it plays in cell division process? How robust are these cellular processes to perturbations in cell shape?

In addressing these exciting fundamental questions we use experimental methods and numerical modeling. In experiments, we combine optical live cell imaging down to single molecule resolution with cell handling and manipulation using micro- and nanoscale fabricated structures. To engineer these structures we use Nanofabrication Research Laboratory's cleanroom facility at ORNL. In explaining the cellular processes we use numerical models based on statistical mechanics, polymer physics and theory of elasticity.

For more information visit our Lab's Web site or contact Dr. Jaan Mannik (e-mail: JMannik@utk.edu). An interested and motivated physics Ph. D. student is welcomed to join this multidisciplinary research effort.

Website: http://www.phys.utk.edu/jmannik/LCBHome.html


Chemical Physics Research and Atmospheric Physics

Our group investigates nature at the boundaries between physics and chemistry which is now called Chemical Physics. Both physics and chemistry graduate students pursue research on a wide variety of topics. Undergraduate students are also an important component in this research and greatly assist the graduate students in their research. The Compton group is well funded with an NSF Grant in Chirality research, a new NSF Grant for the study of Negative Ions, a STAIR/IGERT Grant in Hydrogen Storage and an EPA Grant to study nanomaterials in the environment. One underlying theme of the research involves the study of singly- and multiply-charged negative ions. Included in this research is the characterization of dipole- and quadrupole-bound anions. These are very diffuse and weakly bound anions which play a role in the transport of electrons through gases and along surfaces. Our group is also interested in the detection and characterization of anions in the atmosphere as well as their potential role in the complex physics and chemistry of the atmosphere. Students in the Compton Group may also be involved in ongoing research at Aarhus, Denmark and at the Free Electron Laser (FELIX) in the Netherlands.

The Compton group is well equipped with a large array of experimental apparatuses as well as the full compliment of equipment in the Department of Chemistry (Raman, NMR, CD, UV/VIS, X-Ray, Mass Spectrometrs, etc.). High resolution electron beams and pulsed tunable lasers are employed to study the spectroscopic properties of gaseous molecules in nozzle-jet expansions or nano-materials produced by laser-matter interactions. A technique employing Raman Spectroscopy of samples under liquid nitrogen is used to examine the symmetric (Raman allowed) vibrational energy levels and a Bomem DA8 FTIR spectrometer is employed to record the asymmetric (IR active) vibrational modes.

Every graduate student is assisted in her/his research with computational methods (e.g., Gaussian) and expertise needed to interpret experimental data. Chemical Physics research prepares the student for a wide variety of job and post doctoral opportunities. The last seven group members are now: in charge of the Undergraduate Physics laboratories for the Jr. Colleges in South Carolina, permanent employee at ORNL, employed as a research scientist at Abbot Laboratories, Professor at the University of Mississippi, Faculty member at the University of Calgary, Post Doc at Univ. of Scherbrooke, in charge of AMOP at the FELIX Free Electron Laser in Holland.

Presently, there are openings for two full RA and one split TA/RA appointments.

Further information is available online at: http://web.utk.edu/~rcompton/link.html.

Contact: Dr. Robert N. Compton at rcompton@utk.edu


Condensed Matter Theory: Correlated Electrons, Nanotransport, and Computational Methods

One of the most active areas of research in physics is Condensed Matter. A variety of investigations in recent years have unveiled interesting complex phenomena in several materials, that challenge our understanding of solids and may also lead to technological applications. Prominent among these developments are the areas of (1) High Temperature Superconductors, with critical temperatures that have reached over 150 K and with exotic pairing properties, (2) Colossal Magnetoresistance Manganites, with changes in DC current of many orders of magnitude upon the application of small magnetic fields, and (3) Nanosystems, where quantum effects play a key role. Some members of the Condensed Matter Theory group carry out investigations in these fields and several related ones. The main tools to analyze models for these materials involve computational techniques, since typically there are no small parameters to guide a perturbative expansion, but analytical calculations are also performed. The broad area of investigations outlined in this paragraph is usually referred to as Strongly Correlated Electrons. This field of investigations is also much related with the popular area called Complexity, due to recently unveiled similarities between soft and hard materials.

The UT/Physics Department group working in this research context has a high international visibility, and publishes in prestigious journals such as Physical Review Letters, Science, Physics World, and others. For a list of recent publications see http://sces.phys.utk.edu. The group consists of two professors (Distinguished Professor E. Dagotto and Professor A. Moreo), and several students and postdocs. We receive the frequent visits of collaborators from the US and abroad.

A variety of clusters of PCs are available for the application of computational methods to the study of the materials described above. This includes clusters located at both UT and ORNL, and the combined number of PCs as of April 2005 was close to 300.

The group has a strong relation with the Theory Group of the Condensed Matter Sciences Division (CMSD) of Oak Ridge National Laboratory.


Experimental Nuclear Physics

The research of the low-energy experimental nuclear physics group is focused on the properties of exotic short-lived nuclei and their reactions which are of consequence for the synthesis of the elements in the cosmos. Our group is very active in detector development and has played a leading role in developing charged-particle detector arrays (such as ORRUBA, see http://www.orau.org/stewardship/), a neutron detector array, VANDLE (see http://vandle.oit.utk.edu/vandlewiki/INTRODUCTION) and high efficiency gamma-ray array MTAS (http://pigpen.oit.utk.edu/mtaswiki). We are currently developing a scintillator array for detecting gamma rays called HAGRiD, based on new generation scintillator material LaBr3(Ce) (see http://www.detectors.saint-gobain.com/Brillance380.aspx). A particular strength of the group is the tradition of use of digital data acquisition techniques. Students entering the group will be involved in both hardware development and cutting-edge nuclear physics experiments.

Our experiments are run at national user facilities such as the National Superconducting Cyclotron Laboratory at Michigan State University, with new experimental programs starting at TRIUMF in Canada, and Argonne National Laboratory in Illinois.

Decay of the most exotic nuclei

One main focus of our group is exploratory research on the most exotic nuclei that can be synthesized. We develop ultra-sensitive detection techniques, and then employ them in discovery experiments at very low production rates. We investigate phenomena that occur only in very unstable isotopes, for example, beta-delayed neutron emission using the VANDLE detector. Our expertise in digital electronics has allowed us to engage recently in the super-heavy element research program, a newly re-open nuclear physics frontier.

Direct reactions

Direct reaction techniques include transferring a single nucleon or multiple nucleons, knocking out a nucleon, or simply scattering a nucleus on a target, and are very sensitive to the structure of the nucleus. Recent developments have allowed these techniques to be used with beams of exotic nuclei, some of which are important to understand reactions in stars or in explosive scenarios, such as novae or supernovae.

Please visit us on the web: http://www.phys.utk.edu/expnuclear/ for more information.

Contact: Prof. Robert Grzywacz, rgrzywac@utk.edu or
Associate Prof. Kate Jones, kgrzywac@utk.edu


Multidisciplinary Research in Nanoscale Science and Devices

Dr. Thomas Thundat's research programs at the University of Tennessee and the Oak Ridge National Laboratory focus on mechanical and electronic manifestations of molecular and photonic interactions at interfaces and interphases. Understanding the physics and chemistry involved in the nanomechanical and nano-optical effects of interaction at interafces is important in designing and developing miniature sensors and devices that exploit the nanoscale effects. For example at micro and nanoscale, delicate forces such as photonic, surface tension, thermocapillarity, Marangoni, Knudsen, electrostatic and van der Waals interactions play a significant role because of the large surface to volume ratio in nanoscale systems. Similarly, interaction of photons with electrons in a metal nanostructure, have a range of important applications such as all-optical modulation and switching, surface enhanced Raman spectroscopy (SERS), tip field enhancement a.s.o. However, our understanding of mechanics and function at the nanoscale is far from complete. Recent progress in development of instrumentation that can measure displacements and forces into the nanoscale and sub nanoscale regimes is paving the way for a very exciting convergence of many traditionally separate fields and disciplines ranging from molecular biology to fluid mechanics to quantum mechanics, and to device physics and engineering. Present applied research programs include:

We can support one or two new graduate students full time.

Contacts:
Dr. Thomas Thundat at thundattg@ornl.gov or tthundat@utk.edu
Dr. Ali Passian at passian@utk.edu


Nuclear and Particle Physics at the Spallation Neutron Source

Our goal is to address such questions as the origin of Time Reversal Non-invariance, spontaneous symmetry breaking, and the Big Bang by studying the particle properties of the neutron. Using the Spallation Neutron Source at ORNL as well as other intense neutron sources such NIST's research reactor and the Institut Laue Langevin's (Grenoble, France) high flux reactor, we address such experimental questions as the neutron electric dipole moment, the free neutron lifetime, and the details of parity violation in nuclear processes. The work involves a wide variety of techniques including charged and neutral particle detection, ultra-low temperature cryogenic system, polarized beams, etc. This work should appeal to experimentalists who enjoy hands on physics as well as broad theoretical ideas.

Further information is available online at: http://neutrons.ornl.gov/

Contact: Geoff Greene at ggreene@utk.edu or Nadia Fomin at nfomin@utk.edu


Nuclear Theory: Structure of Rare Isotopes and the Quantum Many-Body Problem

The research of the low-energy nuclear theory group at UT concerns the study of nuclei and nuclear astrophysics, which addresses the origin of the elements, the structure and limits of nuclei, and the evolution of the cosmos. The main questions for this field are: What binds protons and neutrons into stable nuclei and rare isotopes? What is the origin of simple patterns in complex nuclei? When and how did the elements from iron to uranium originate? What causes stars to explode? The new and exciting frontier in nuclear theory lies in the description of rare and short-lived nuclei. These nuclei have unusual ratios of neutrons to protons. In this unique situation, important inter-nucleon interactions are isolated and amplified. The weak binding of neutron-to-proton asymmetric systems add additional flavor to the nuclear many-body problem. Exciting new properties are, e.g. neutron halos, proton radioactivity, and changes in shell structure.

The UT/ORNL nuclear theory group consists of Drs. D. J. Dean, G. Hagen, W. Nazarewicz, T. Papenbrock, several long- and short-term visitors, postdoctoral associates, and students. We investigate many aspects of the nuclear many-body problem with particular emphasis on rare isotopes. We employ microscopic methods (involving density functional theory, coupled cluster theory, Monte Carlo simulation, and shell model diagonalizations), and tackle theoretical challenges with pencil and paper, PCs, and the world's most powerful supercomputers. We also apply our ideas to other many-body problems, e.g., to ultracold atom gases. For more details, please see the titles of our recent publications, and come to our seminar. The group has several international visitors each year, and collaborates with experimental nuclear physicists at UT and ORNL. A few potential projects are described below.

Theoretical Description of Nuclear Fission

Nuclear fission is one of the best examples of nuclear large-amplitude collective motion. It is also a complicated many-body process which is difficult to treat on the microscopic level. Various nuclear structure models have been applied to fission barriers, lifetimes, and mass/charge distributions, and they provided good overall description of the phenomenon and, in many cases, detailed predictions. On the other hand, it is also true that the microscopic description of fission, based on effective nucleon-nucleon interactions, still does not exist. The aim of this project is to attack the problem of spontaneous fission using modern theoretical methods and computational tools. This project is supported by the grant from the National Nuclear Security Administration.

Contact: Dr. Witold Nazarewicz at witek@utk.edu.

First-principles nuclear structure calculations with the coupled-cluster method

We are using the coupled-cluster methods for first-principles calculations of selected nuclei that are of current experimental and theoretical interest. Within this approach, a similarity-transformed Hamiltonian is constructed that decouples from few-particlefew-hole excitations. The application of this method involves diagrammatic derivations, and a numerical implementation of the derived expressions. Students working in this area would actively participate in code development and calculations for relevant benchmark nuclei. The scientific questions we address relate to the role of three-nucleon forces in nuclei, and the evolution of shell structure in exotic nuclei.

Contact: Dr. Thomas Papenbrock at tpapenbr@utk.edu.


Particle Physics: Study of Neutrino Properties

When in 1930 Wolfgang Pauli invented neutrino particles for the explanation of beta-decay experiments he bet a case of champagne that nobody ever would be able to detect these particles. Nowdays detection of neutrinos is a field of precision experimentation in Physics: we recently learned in our KamLAND experiment that neutrinos have masses and can transform from one type to another. The next set of  questions to study in neutrino experiments are the hierarchy of neutrino masses and whether CP-symmetry is violated in neutrino interactions. Such a violation might be a mechanism of cosmological leptogenesis and an explanation of matter-antimatter asymmetry in the Universe.

The key to such measurements is the determination of an important mixing angle theta_13 between the neutrino mass eigenstates.Theta_13 will be measured in the "Double Chooz" experiment that is being constructed at a nuclear power plant in France and where UT is participating in the construction of the first of two neutrino detectors. We invite interested graduate students to participate in the construction of the second Double Chooz detector in France next year and also in the following neutrino measurements and data analysis in the international team of researchers. We anticipate a PhD project to be ready in 2012.

We also invite graduate students to participate in another neutrino project, NOvA, where a 2 GeV neutrino beam will be directed from the NuMI source at FermiLab to the huge, 15kt, detector to be constructed in Minnesota at a distance of 810 km from the neutrino production target at FermiLab. This experiment will be able to compare neutrinos with antineutrinos produced by the particle beams, will determine the neutrino mass hierarchy and observe possible CP-violation effects. We expect the student to be involved in the initial tests of the detector prototype in neutrino beam at FermiLab starting next year, but also in simulations, and data analysis. Expected PhD project completion is 2012-2013.

We know that neutrino has very small but nonzero mass. Howeverits value never been measured. "Majorana" double beta decay experiment could have enough sensitivity to measure it. We are looking for a graduate student who like to get his/her hands on experience working with ultra pure materials in the state of the art sensitivity range. Work will include extensive communication with other members of the large Majorana collaboration between dozen of Universities and three US National Laboratories.

Further information is available online at the following sites:

Contacts: For "Double Chooz" and "NOvA," contact Dr. Yuri Kamyshkov, office 505 in the Nielsen Physics Building, telephone 865-974-6777 or e-mail kamyshkov@utk.edu. For "KamLAND" and "Majorana," contact Dr. Yuri Efremenko, office 503 in Nielsen Physics Building, telephone 865-974-7857 or e-mail yefremen@utk.edu


Relativistic Heavy Ion Physics

The research of the Relativistic Heavy Ion Physics (RHIP) group is focused on the study of nuclear matter at extreme temperatures and densities, which is a new and exciting field on the borderline between nuclear and high energy physics. At these extreme conditions of temperature and density nuclear matter will undergo a phase transition to a Quark-Gluon Plasma. In this new phase nuclear matter no longer consists primarily of protons and neutrons, but instead consists of deconfined quarks and gluons in a state that mostly resembles a superfluid liquid. Experimentally, we are creating high temperature nuclear matter by colliding heavy nuclei (heavy ions) at very high energies (ultrarelativistic energies) at nuclear accelerators.

Specifically, we are working within two large collaborations: the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, Long Island, New York, and the ALICE Collaboration at the Large Hadron Collider (LHC) at CERN, Geneva, Switzerland. We also collaborate closely with researchers in the High Energy Reactions Group in the Physics Division at ORNL.

In general, the RHIP group has two to four students involved in our research at different stages in their graduate studies, a post-doc, and three professors, Christine Nattrass, Ken Read and Soren Sorensen. We are always looking for new students, so please do not hesitate to check us out at: http://www.phys.utk.edu/rhip/ or contact us directly through the contact info at: http://www.phys.utk.edu/rhip/RHIP_People.htm. We are in particular looking for students with an interest in working within large collaborations at the cutting edge of science and technology and with an interest and willingness to travel extensively to the large accelerator centers in New York and Switzerland.


Soft Matter Physics and Biophysics (contact Dr. Alexei P. Sokolov)

Soft Matter Physics is a relatively new but very fast growing and exciting field of Physics. It studies phenomena in complex materials with many degrees of freedom and strong interplay between enthalpy and entropy. These materials have broad applications from energy to biomedical fields. There are four major direction of research in our group:

Polymer Dynamics, Glass Transition: Molecular motion is the key to many macroscopic properties of soft materials (polymers, colloids, glass-forming and biological systems, etc.). The main goal of our studies in this direction is fundamental understanding of molecular motions and their relationship to macroscopic properties of polymers and other glass-forming materials. Among the major topics, we study the glass transition phenomenon, viscoelastic and mechanical properties, electrical conductivity, influence of chemical structure of the molecules on the dynamics and macroscopic properties of the materials.

Dynamics of Biological Macromolecules: Activity and function of biological systems are defined by their dynamics. Understanding the basic parameters that control molecular motions in biological systems, and understanding the relationship between molecular dynamics and biological functions are the main goals of our research in this direction. Among major topics, we also study role of solvents in protein dynamics, activity and stability and we are developing formulations for long-term preservation of biological molecules.

Nano-composite and Nano-structured Materials: Addition of small nano-particles to polymers can tremendously affect their properties. We study the influence of nano-fillers (carbon nano-tubes, silica and polymeric particles, graphene) on mechanical and electrical properties of polymers, their dynamics and glass transition. We also study how confinement to small volume (various nanostructures) affects mechanical properties and dynamics of the materials. We analyze various kinds of nano-structures, including polymeric and biological (e.g. viruses).

Nano-optics, Plasmonics: We are developing scanning nano-Raman spectroscopy based on the apertureless near-field optics. It employs gigantic local enhancement of electrical field of light by plasmonic (particular metallic) structures. We already achieved Raman imaging of semiconducting structures with spatial resolution ~20 nm, far beyond the diffraction limit of light. We are also developing plasmonic structures for molecular-level sensing based on surface-enhanced Raman scattering. In our studies we use neutron and light scattering techniques, dielectric and mechanical relaxation spectroscopy, and we actively collaborate with groups performing MD-simulations. Our group is a part of Soft Materials Group at ORNL.

Talented students who are not afraid of scientific challenges are welcome to join our group: please see our Web site at: http://www.chem.utk.edu/sokolov/index.html.

Alexei P. Sokolov
Governor's Chair, Professor of Chemistry and Physics
663 Buehler Hall, e-mail: sokolov@utk.edu
The best way to contact me is via e-mail.


Theoretical Biological Physics: Spatial Stochastic Dynamics in Biological Networks

I am looking for a few graduate students and one postdoctoral scholar to work on application of statistical physics, stochastic processes, and nonlinear dynamics to the dynamical behavior and the collective phenomena in complex biological systems. In particular, we are interested in the effect of network topology and intrinsic/extrinsic noise on the dynamics of key components in the biological networks of our interest. We also have a keen interest in application of non-equilibrium statistical physics to the spreading phenomena of infectious diseases. The prospective graduate students are expected to be familiar with graduate level (preferably non-equilibrium) statistical physics, to demonstrate an interest in learning stochastic processes and nonlinear dynamics, and to work closely with both experimental and theoretical biology colloborators. However, the most important qualification for those positions are a demonstrated burning desire to jump into the wonderful world of the interface between physics and biology.

Please email Jaewook Joo at jjoo1@utk.edu if you are to discuss the above open positions.


Theoretical High Energy Physics: Strings and Quantum Gravity

The High Energy Theory group is currently working in the rapidly developing subject of black holes and other extended objects in string theory. Despite its shortcomings, string theory is still the only viable quantum theory of gravity. Recent results on black holes, D-branes, etc. are very exciting, having considerably advanced our understanding of quantum aspects of gravity such as thermodynamicalproperties of black holes (e.g., entropy), Hawking radiation and the information loss paradox. Their cosmological implications are also being investigated.

For more information, visit our Web site, or contact Dr. George Siopsis (e-mail: siopsis@tennessee.edu)

Web Site: http://aesop.phys.utk.edu



 

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