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, in search for answers to fundamental questions such as: Do all fundamental forces unify? What is dark matter? Is there evidence for quantum gravity and extra dimensions?
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Are micro black holes potentially created in high-energy proton collisions? Is nature supersymmetric? We also work on the development of future collider experiments, with a focus on potential muon colliders. Students in our group build upgrades for the CMS experiment, operate the detector during data-taking, and analyze data to search for new particles and look for deviations from known processes. Computational work is an essential component of a PhD in this group. Past experience with coding is a plus, but in any case, students will be expected to develop coding competency in their first year with the group. Graduate students learn about and apply different particle detection techniques and statistical analysis methods, including machine learning. We open new avenues by developing smart search strategies to not overlook any exciting corner where new physics could show up. The group’s hardware work is centered around charged particle detection with the CMS Tracker. The group has helped build, install, and now operates a new instrument as part of the CMS detector at CERN that measures inclusively the rate of particles produced in proton-proton collisions at the LHC to derive the luminosity that is essential to all particle searches. We are now working towards an upgrade of the tracker for the High-Luminosity LHC, working areas that include sensor R&D, module production, data acquisition, and real-time tracking. Prototype sensors and data acquisition systems are tested in our laboratory at UT and in test beams at Fermilab, Los Alamos, and CERN. We collaborate with people at universities and labs all around the world, and students will typically spend some time in Switzerland.
Contact
If you’re interested in the CMS group, contact any of the PIs:
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.
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The accelerator physics group is seeking qualified graduate students interested in doing research in the following areas:
- Computational, theoretical and experimental studies of the dynamics of high-intensity charged particle beams, with emphasis on multi-particle and collective effects
- Development of superconducting cavity technology
- Development of laser-beam interaction technology such as H- laser-assisted injection stripping.
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 neutrons.ornl.gov.
Contact
Interested candidates should contact UT adjunct faculty Sarah Cousineau or Jeffrey Holmes.
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.
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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.
Contact
For more information visit our Lab’s Web site or contact Dr. Jaan Mannik. An interested and motivated physics PhD student is welcomed to join this multidisciplinary research effort.
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.
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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, a neutron detector array; VANDLE; and high efficiency gamma-ray array MTAS.
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We are currently developing a scintillator array for detecting gamma rays called HAGRiD, based on new generation scintillator material LaBr3(Ce). 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.
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.
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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.
Contact
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.
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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, 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.
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-particle few-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
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.
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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:
- KamLAND Web page in Japan: http://www.awa.tohoku.ac.jp/KamLAND/index.html
- Double Chooz experiment in France: http://doublechooz.in2p3.fr/Status_and_News/status_and_news.php
- NOvA experiment at FermiLab: http://www-nova.fnal.gov/. [See the write-up on the NOvA experiment in Symmetry, a joint publication of Fermilab and SLAC.]
- Majorana experiment at DUSEL: http://majorana.npl.washington.edu/
Contact
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.
Quantum Materials Synthesis and Characterization
Quantum materials, in general, are materials whose electronics properties are understood by laws of quantum mechanics. Interactions between electrons at the atomic and subatomic scales result in exotic quantum phenomena, such as interference, tunneling, quantum fluctuations, quantum entanglement, and topologically non-trivial behaviors.
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We have a strong team (Haidong Zhou, Jian Liu, Joon Sue Lee, and Wonhee Ko) working on quantum materials synthesis including bulk single crystal growth, thin film growth, and heterostructure deposition, physical properties characterization, evidencing the quantum phenomena, and manipulation of the quantum behavior for potential applications. We welcome highly motivated students to contribute to our efforts and enjoy the scientific adventure with us.
Zhou’s research interests are to discovery new materials possessing abnormal physical properties, such as geometrically frustrated magnetism showing quantum spin behaviors, multiferroicity, orbital ordering, and metal-insulator transitions. The strategies are to grow bulk single crystals of them using various methods including floating zone technique in image furnace, flux method, and chemical vapor transport method, and thereafter study them by x-ray scattering, low temperature and high magnetic field measurements, and neutron scattering measurements.
Liu’s projects span various topics, such as topology-correlation interplay, quantum critical phenomena, quantum magnetism, metal-insulator transition, and unconventional superconductivity. The focus is to identify, design, and create toy-model materials where we can tailor the dimensionality and the symmetry operations to capture fundamental physics of model Hamiltonians, such as the Hubbard model and Heisenberg model. This goal is achieved by exploiting advanced bottom-up synthesis technique, novel elastic strain engineering, multi-modal synchrotron x-ray scattering, and ultralow temperature high magnetic field measurements. In many cases, the observed unusual quantum phenomena also afford unparalleled functionalities for potential applications. Liu’s work involves broad collaborations within the department both experimentally and theoretically. Multiple positions are currently available for students to join Liu’s research on emergent phenomenain quantum condensed matters, which include atomically engineered quantum heterostructures and quantum materials.
Lee employs molecular beam epitaxy to synthesize high-quality thin films and nanostructures of quantum materials, by precise control over layer-by-layer growth in ultrahigh vacuum environment. His research group develops low-dimensional semiconductor systems, such as 1D nanowires, 2D electron gases, and networks of quantum wires by selective area growth, as well as topological materials including topological insulators and semimetals. His research extends to studies on quantum devices based on the grown quantum materials for unveiling fundamental quantum phenomena and exploring future device applications.
Ko’s research focuses on nanoscale to atomic-scale characterization of the quantum materials using novel microscopy techniques.
Contact
We welcome highly motivated students to contribute to our efforts and enjoy the scientific adventure with us.
Quantum Technologies
The Quantum Technologies Group is exploring the bizarre world of quantum mechanics. Its properties, such as superposition, coherence, entanglement, teleportation, etc., have given rise to various paradoxes (Schrodinger’s cat, the Einstein-Podolsky-Rosen paradox, etc.).
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Back in the early ’80s, Feynman was among the first to suggest that these principles may enable us to process information at much faster speeds than any classical computer. Ever since, people have been trying to harness the power of quantum mechanics and build a quantum computer. This subject is still in its infancy, but already industry giants, such as Microsoft, IBM and Google, are trying to make use of a quantum computer. Another promising application of quantum mechanics is in cryptography. It provides unprecedented means of transmitting encrypted information over a public channel. Quantum information and quantum computation are rapidly developing arenas of basic as well as applied research. The group performs research at both UT and ORNL, and anticipates several RA position openings in both theory and experiment.
Contact
For more information, e-mail: quantum@tennessee.edu
Website: quantum.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. At these extreme conditions of temperature and density nuclear matter will undergo a phase transition to a Quark-Gluon Plasma.
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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
Our future graduate students will work on the sPHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, Long Island, New York. 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 two professors, Christine Nattrass and Ken Read.
Contact
Interested students are always welcome to contact us, so please do not hesitate to check us out at: http://www.phys.utk.edu/rhip/ or contact us directly at our emails below.
Theoretical Biophysics and Non-Equilibrium Statistical Mechanics
Living systems at all scales ranging from populations of animals to replicating DNA molecules are dynamic, fluctuating, and explicitly out-of-equilibrium. Our group is interested in developing analytic and computational approaches to study such systems.
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We use tools from statistical physics to elucidate the evolutionary dynamics of spatially distributed populations, pattern morphogenesis on the surfaces of cells, the phase separation of nuclear material in a microbial cell, and many other biological processes. This work is necessarily collaborative, as the best theories are those that make contact with experiment. Our group interacts with, among others, the Mannik group at UTK, the Sweeney group at Yale, and the Tran group at Utrecht University.
We are also interested in fundamental questions in statistical mechanics, which are often addressed by appealing to simplified models and more experimentally accessible systems in condensed matter. For example, our group has started characterizing the motion of domain walls in ferroelectric materials, in collaboration with Petro Maksymovych at Oak Ridge National Laboratory. These walls, in the presence of an applied electric field, move with a velocity that is influenced by both thermal fluctuations and disorder within the material. We aim to build a theory of this driven motion. We are also interested in pattern formation in strongly driven systems. Our recent work builds a field-theoretic approach to understanding a stripe formation in a driven, phase-separating lattice gas model, first developed by our collaborators.
Contact
Students can find a wide range of projects depending on their skills and interests. To get an idea of the scope of the work, it may be helpful to consult our publication list.
The best way to get to know us is to contact me at “mlavrent@utk.edu” if you are interested!