“An Open World of Physics: a Celebration of Sankar Das Sarma's
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Victor Galitski (UMC)
Title: “Strong Correlations Meet Topology in Exotic Insulators” Abstract: Topological states of quantum matter represent a rapidly developing area of research, where a fascinating variety of exotic phenomena occur, ranging from unusual transport properties to fractionalized excitations that may emerge at system’s defects. Of particular recent interest has been the topic of strongly-interacting topological phases, where electronic correlations and topology both play an important role. In this talk, I will review recent theoretical and experimental work on a relatively new class of such interacting topological material system – topological Kondo insulators, which appear as a result of interplay between strong correlations and spin-orbit interactions. I will start by explaining in simple terms the basics of topological quantum matter, including the by now standard theory of topological band insulators. Then, I will use these concepts to show that the conduction electrons and localized magnetic moments in certain heavy fermion compounds hybridize to give rise to a topological insulating behavior. I will explain key experimental results, which have confirmed our predictions in the Samarium hexaboride heavy fermion compound, where the long-standing puzzle of the residual low- temperature conductivity has been shown to originate from topological surface states. I will also mention several recent theory-experiment collaborative projects that led to the development of a “topological device” and new methods to extend topological behavior in Kondo insulators from a few Kelvin to room temperature. In conclusion, I will discuss a series of recent puzzling experiments, which unexpectedly observed quantum oscillations, typical to a metal, coming from an inert, insulating bulk of Kondo insulators, which may represent a smoking gun of a new fractionalized state of matter. -
Controlling the Surfaces of Atomically Thin Materials to Create New Electronic Phases Michael S
Controlling the surfaces of atomically thin materials to create new electronic phases Michael S. Fuhrer School of Physics, New Horizons Centre Monash University Center for Nanophysics and Advanced Materials Michael S. Fuhrer University of Maryland Monash University Michael S. Fuhrer Monash University Michael S. Fuhrer Monash University Michael S. Fuhrer Monash University Michael S. Fuhrer Monash University Michael S. Fuhrer Monash University Michael S. Fuhrer Monash University Monash University • One of “Group of Eight” in Australia • Largest University in Australia: • 60,000 students total on 7 campuses (incl. South Africa and Malaysia) • 30,000 students at Clayton campus • Ranked 91st in the world (Times Higher Education); 69th in the world (QS); and top 150 (ARWU) Michael S. Fuhrer Monash University New Horizons Centre 23,000 m2 building, opened July 2013 Foster new interdisciplinary collaborative efforts: Brings together Monash researchers in Advanced Materials Physics, Chemistry, Engineering (Materials, Mechanical, Medical etc.) with Advanced Manufacturing CSIRO researchers Physics laboratories built to NIST-A vibration standards. Michael S. Fuhrer Monash University Research Facilities in Monash precinct Monash Centre for Electron Microscopy Melbourne Centre for Nanofabrication Electron Microscopy including double-aberration- Cleanroom for device fabrication, including 100 corrected TEM , SEM, FIB, atom probe keV electron beam lithography Australian Synchrotron Currently 8 beamlines Michael S. Fuhrer Monash University Monash Centre for Atomically Thin Materials Director: Michael Fuhrer (School of Physics, Faculty of Science) Co-Director: Dan Li (Dept. of Materials Engineering, Faculty of Engineering) Goal: Establish Monash as the hub for 2D material research in Australia Strategy: Seed-fund new collaborative research at Monash Form strong links with international partners Coordinate major bids for external funding Michael S. -
Shaffique Adam a Self-Consistent Theory for Graphene Transport
A self-consistent theory for graphene transport Shaffique Adam Collaborators: Sankar Das Sarma, Piet Brouwer, Euyheon Hwang, Michael Fuhrer, Enrico Rossi, Ellen Williams, Philip Kim, Victor Galitski, Masa Ishigami, Jian-Hao Chen, Sungjae Cho, and Chaun Jang. Schematic 1. Introduction - Graphene transport mysteries - Need for a hirarchy of approximations - Sketch of self-consistent theory: discussion of ansatz and its predictions 2. Characterizing the Dirac Point - What the Dirac point really looks like - Comparison of self-consistent theory and energy functional minimization results 3. Quantum to classical crossover 4. Effective medium theory 5. Comparison with experiments Introduction to graphene transport mysteries High Density Low Density Hole carriers Electron carriers E electrons kx ky holes n Figure from Novoselov et al. (2005) Vg n Fuhrer group (unpublished) 2006 ∝ - Constant (and high) mobility over a wide range of density. Dominant scattering mechanism? - Minimum conductivity plateau ? - Mechanism for conductivity without carriers? What could be going on? Graphene - Honeycomb lattice: Dirac cone with trigonal warping, - Disorder: missing atoms, ripples, edges, impurities (random or correlated) - Interactions: screening, exchange, correlation, velocity/disorder renormalization - Phonons - Localization: quantum interference - Temperature - ... Exact solution is impossible -> reasonable hierarchy of approximations Any small parameters? - For transport, we can use a low energy effective theory i.e. Dirac Hamiltonian. Corrections, -
Curriculum Vitae of Victor M. Yakovenko
Curriculum Vitae of Victor M. Yakovenko I certify that this Curriculum Vitae is accurate and complete. Signature: March 8, 2021 1 Personal Information Victor M. Yakovenko Department of Physics, University of Maryland, College Park, MD 20742-4111, USA Professor, promoted July 1, 2004 http://physics.umd.edu/~yakovenk/ Education 1984 { 1987 : Landau Institute for Theoretical Physics, Moscow Ph.D. in theoretical physics, advisor: L. P. Gor'kov 1978 { 1984 : Moscow Physical-Technical Institute M.S. in physics, advisor: S. A. Brazovskii Employment 7/1/2004 { present : Full Professor, Department of Physics, University of Maryland 7/1/1999 { 6/30/2004 : Associate Professor, Department of Physics, University of Maryland 8/17/1993 { 6/30/1999 : Assistant Professor, Department of Physics, University of Maryland 1991 { 1993 : Research Associate, Department of Physics and Astronomy, Rutgers University, advisor: E. Abrahams 1987 { 1991 : Research Scientist, Landau Institute for Theoretical Physics, Moscow, department of I. E. Dzyaloshinskii Visiting Positions 1{2/2009 : Santa Fe Institute and Los Alamos National Laboratory, Santa Fe, New Mexico 8{11/2008 : Laboratoire de Physique Th´eorique et Mod`elesStatistiques, Universit´eParis-Sud, Orsay 8/1991 : Interdisciplinary Research Center in Superconductivity, Cambridge University, Britain 4{8/1990 : Institute for Scientific Interchange, Turin, Italy 5{7/1989 : Laboratoire de Physique des Solides, Universit´eParis-Sud, Orsay, France Participation in long-term workshops at the Kavli Institute for Theoretical Physics, Santa Barbara, California 8/2009 : \The Physics of Higher Temperature Superconductivity" 4{5/2009 : \Low Dimensional Electron Systems" 12/2007 : \Sr2RuO4 and Chiral p-wave Superconductivity" 3{4/2005 : \Quantum Phase Transitions" 5{6/2004 : \Exotic Order and Criticality in Quantum Matter" 10{12/2002 : \Realistic Theories of Correlated Electron Materials" 1 2 Research, Scholarly, and Creative Activities The name of V. -
Electronic Structure of Full-Shell Inas/Al Hybrid Semiconductor-Superconductor Nanowires: Spin-Orbit Coupling and Topological Phase Space
Electronic structure of full-shell InAs/Al hybrid semiconductor-superconductor nanowires: Spin-orbit coupling and topological phase space Benjamin D. Woods,1 Sankar Das Sarma,2 and Tudor D. Stanescu1, 2 1Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506, USA 2Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland, 20742-4111, USA We study the electronic structure of full-shell superconductor-semiconductor nanowires, which have recently been proposed for creating Majorana zero modes, using an eight-band ~k · ~p model within a fully self-consistent Schrodinger-Poisson¨ scheme. We find that the spin-orbit coupling induced by the intrinsic radial electric field is generically weak for sub-bands with their minimum near the Fermi energy. Furthermore, we show that the chemical potential windows consistent with the emergence of a topological phase are small and sparse and can only be reached by fine tunning the diameter of the wire. These findings suggest that the parameter space consistent with the realization of a topological phase in full-shell InAs/Al nanowires is, at best, very narrow. Hybrid semiconductor-superconductor (SM-SC) nanowires butions) and ii) the electrostatic effects (by self-consistently have recently become the subject of intense research in the solving a Schrodinger-Poisson¨ problem). We note that these context of the quest for topological Majorana zero modes are crucial issues for the entire research field of SM-SC hy- (MZMs) [1,2]. Motivated by the promise of fault-tolerant brid nanostructures, but they have only recently started to be topological quantum computation [3,4] and following con- addressed, and only within single-orbital approaches [27–30]. -
Sankar Das Sarma 3/11/19 1 Curriculum Vitae
Sankar Das Sarma 3/11/19 Curriculum Vitae Sankar Das Sarma Richard E. Prange Chair in Physics and Distinguished University Professor Director, Condensed Matter Theory Center Fellow, Joint Quantum Institute University of Maryland Department of Physics College Park, Maryland 20742-4111 Email: [email protected] Web page: www.physics.umd.edu/cmtc Fax: (301) 314-9465 Telephone: (301) 405-6145 Published articles in APS journals I. Physical Review Letters 1. Theory for the Polarizability Function of an Electron Layer in the Presence of Collisional Broadening Effects and its Experimental Implications (S. Das Sarma) Phys. Rev. Lett. 50, 211 (1983). 2. Theory of Two Dimensional Magneto-Polarons (S. Das Sarma), Phys. Rev. Lett. 52, 859 (1984); erratum: Phys. Rev. Lett. 52, 1570 (1984). 3. Proposed Experimental Realization of Anderson Localization in Random and Incommensurate Artificial Structures (S. Das Sarma, A. Kobayashi, and R.E. Prange) Phys. Rev. Lett. 56, 1280 (1986). 4. Frequency-Shifted Polaron Coupling in GaInAs Heterojunctions (S. Das Sarma), Phys. Rev. Lett. 57, 651 (1986). 5. Many-Body Effects in a Non-Equilibrium Electron-Lattice System: Coupling of Quasiparticle Excitations and LO-Phonons (J.K. Jain, R. Jalabert, and S. Das Sarma), Phys. Rev. Lett. 60, 353 (1988). 6. Extended Electronic States in One Dimensional Fibonacci Superlattice (X.C. Xie and S. Das Sarma), Phys. Rev. Lett. 60, 1585 (1988). 1 Sankar Das Sarma 7. Strong-Field Density of States in Weakly Disordered Two Dimensional Electron Systems (S. Das Sarma and X.C. Xie), Phys. Rev. Lett. 61, 738 (1988). 8. Mobility Edge is a Model One Dimensional Potential (S. -
Table of Contents (Print)
NEWSPAPER 97 Kinetic energy (vertical) of deuterons after fragmentation of deuterium molecules in a pump-probe experiment, for a given time delay (horizontal) between the pump and the probe pulses. Colors denote the number of deuterons, with orange-yellow being the highest. See article 193001. PHYSICAL REVIEW LETTERS PRL 97 (19), 190201– 199901, 10 November 2006 (280 total pages) Contents Articles published 4 November–10 November 2006 VOLUME 97, NUMBER 19 10 November 2006 General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. Quantum Feedback Control for Deterministic Entangled Photon Generation .......................................... 190201 Masahiro Yanagisawa General Approach to Quantum-Classical Hybrid Systems and Geometric Forces ..................................... 190401 Qi Zhang and Biao Wu Condensation of N Interacting Bosons: A Hybrid Approach to Condensate Fluctuations ............................. 190402 Anatoly A. Svidzinsky and Marlan O. Scully Dipole Polarizability of a Trapped Superfluid Fermi Gas . ............................................................ 190403 A. Recati, I. Carusotto, C. Lobo, and S. Stringari Loschmidt Echo in a System of Interacting Electrons ................................................................ 190404 G. Manfredi and P.-A. Hervieux Detection Scheme for Acoustic Quantum Radiation in Bose-Einstein Condensates . ................................. 190405 Ralf Schu¨tzhold Quantum Stripe Ordering in Optical Lattices . ........................................................................ -
Theory and Modeling in Nanoscience
Theory and Modeling in Nanoscience Report of the May 10–11, 2002, Workshop Conducted by the Basic Energy Sciences and Advanced Scientific Computing Advisory Committees to the Office of Science, Department of Energy Cover illustrations: TOP LEFT: Ordered lubricants confined to nanoscale gap (Peter Cummings). BOTTOM LEFT: Hypothetical spintronic quantum computer (Sankar Das Sarma and Bruce Kane). TOP RIGHT: Folded spectrum method for free-standing quantum dot (Alex Zunger). MIDDLE RIGHT: Equilibrium structures of bare and chemically modified gold nanowires (Uzi Landman). BOTTOM RIGHT: Organic oligomers attracted to the surface of a quantum dot (F. W. Starr and S. C. Glotzer). Theory and Modeling in Nanoscience Report of the May 10–11, 2002, Workshop Conducted by the Basic Energy Sciences and Advanced Scientific Computing Advisory Committees to the Office of Science, Department of Energy Organizing Committee C. William McCurdy Co-Chair and BESAC Representative Lawrence Berkeley National Laboratory Berkeley, CA 94720 Ellen Stechel Co-Chair and ASCAC Representative Ford Motor Company Dearborn, MI 48121 Peter Cummings The University of Tennessee Knoxville, TN 37996 Bruce Hendrickson Sandia National Laboratories Albuquerque, NM 87185 David Keyes Old Dominion University Norfolk, VA 23529 This work was supported by the Director, Office of Science, Office of Basic Energy Sciences and Office of Advanced Scientific Computing Research, of the U.S. Department of Energy. Table of Contents Executive Summary.......................................................................................................................1 -
Curriculum Vitae
Curriculum Vitae 1 Personal Information Victor M. GALITSKI Professor of Physics in the Department of Physics within the College of Computer, Mathematical, and Natural Sciences (CMNS) at the University of Maryland, College Park Fellow of the Joint Quantum Institute Business Address: Physics Department, University of Maryland College Park, MD 20742-4111 Phone: 301.405.6107 Fax: 301.314.9465 E-mail: [email protected] WWW: http://terpconnect.umd.edu/∼galitski/ Degrees August 2002 : Ph.D. in theoretical condensed matter physics with the focus on superconductivity Thesis title: \Quantum Fluctuations in Superconductors" (Advisor: Prof. A. Larkin) Theoretical Physics Institute, University of Minnesota, Minneapolis August 1999 : Ph.D. in applied math (asymptotic methods for solving partial differential equations applied to magneto-hydrodynamics of turbulent flows) Thesis title: \Spectrum of Parker's equations" (Advisor: Prof. D. Sokoloff) Moscow Engineering Physics Institute (MEPhI), Moscow, Russia April 1998 : M.S. degree in Engineering (diploma Cum Laude), MEPhI Employment 04/2019 onwards : Chesapeake Chair of Theoretical Physics, University of Maryland, College Park, MD 07/2013 onwards : Full Professor, Department of Physics, University of Maryland, College Park, MD 01/2016 onwards : Honorary Professor at Monash University, Melbourne, Australia 06/2017 onwards : Editor, Annals of Physics, New York, NY 09/2006 onwards : Fellow of the Joint Quantum Institute, University of Maryland, College Park 07/2011 { 6/2013 : Associate Professor with tenure, -
Topics in Cold Atoms Related to Quantum Information Processing and a Machine Learning Approach to Condensed Matter Physics
Topics in Cold Atoms Related to Quantum Information Processing and A Machine Learning Approach to Condensed Matter Physics Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Jiaxin Wu, B.S., M.S. Graduate Program in Physics The Ohio State University 2019 Dissertation Committee: Professor Tin-Lun Ho, Advisor Professor Nandini Trivedi Professor Rolando Vald´es Aguilar Professor Eric Braaten c Copyright by Jiaxin Wu 2019 Abstract This thesis is mainly focused on three topics: Majorana excitations in a number- conserving model, manipulation of quasi-particle excitations in quantum Hall systems, and a new machine learning algorithm to find the ground states of a general Hamil- tonian. In condensed matter physics, Majorana fermions are emergent excitations which are candidates for quantum memory and topological quantum computation. The first and simplest model revealing these excitations does not conserve particle number. Its experimental realization in solid state materials is difficult and still under debate. In comparison, cold atoms provide an alternative platform to realize these exotic excitations. However, cold atoms experiments require the system to be number- conserving. Theoretically, it is not yet clear whether there is a model realizable in cold atoms that also hosts these exotic excitations. In this thesis, we investigate such a number-conserving model and show that it has the same phase diagram and very similar excitations. Although the ground state degeneracy, as one of the signature properties of the original Majorana model crucial for quantum memory, is not present when the total particle number is fixed, one can recover the degeneracy by allowing tunnelling to change the total particle number. -
Transport of Dirac Electrons in a Random Magnetic Field in Topological Heterostructures
San Jose State University SJSU ScholarWorks Faculty Research, Scholarly, and Creative Activity 6-6-2016 Transport of Dirac electrons in a random magnetic field in topological heterostructures Hilary M. Hurst University of Maryland, [email protected] Dimitry K. Efimkin University of Maryland Victor Galitski University of Maryland Follow this and additional works at: https://scholarworks.sjsu.edu/faculty_rsca Part of the Condensed Matter Physics Commons Recommended Citation Hilary M. Hurst, Dimitry K. Efimkin, and Victor Galitski. "Transport of Dirac electrons in a random magnetic field in opologicalt heterostructures" Physical Review B (2016). https://doi.org/10.1103/ physrevb.93.245111 This Article is brought to you for free and open access by SJSU ScholarWorks. It has been accepted for inclusion in Faculty Research, Scholarly, and Creative Activity by an authorized administrator of SJSU ScholarWorks. For more information, please contact [email protected]. PHYSICAL REVIEW B 93, 245111 (2016) Transport of Dirac electrons in a random magnetic field in topological heterostructures Hilary M. Hurst,1 Dmitry K. Efimkin,1 and Victor Galitski1,2 1Joint Quantum Institute and Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA 2School of Physics, Monash University, Melbourne, Victoria 3800, Australia (Received 8 March 2016; published 6 June 2016) We consider the proximity effect between Dirac states at the surface of a topological insulator and a ferromagnet with easy plane anisotropy, which is described by the XY model and undergoes a Berezinskii-Kosterlitz-Thouless (BKT) phase transition. The surface states of the topological insulator interacting with classical magnetic fluctuations of the ferromagnet can be mapped onto the problem of Dirac fermions in a random magnetic field. -
Nanoelectronics, Nanophotonics, and Nanomagnetics Report of the National Nanotechnology Initiative Workshop February 11–13, 2004, Arlington, VA
National Science and Technology Council Committee on Technology Nanoelectronics, Subcommittee on Nanoscale Science, Nanophotonics, and Nanomagnetics Engineering, and Technology National Nanotechnology Report of the National Nanotechnology Initiative Workshop Coordination Office February 11–13, 2004 4201 Wilson Blvd. Stafford II, Rm. 405 Arlington, VA 22230 703-292-8626 phone 703-292-9312 fax www.nano.gov About the Nanoscale Science, Engineering, and Technology Subcommittee The Nanoscale Science, Engineering, and Technology (NSET) Subcommittee is the interagency body responsible for coordinating, planning, implementing, and reviewing the National Nanotechnology Initiative (NNI). The NSET is a subcommittee of the Committee on Technology of the National Science and Technology Council (NSTC), which is one of the principal means by which the President coordinates science and technology policies across the Federal Government. The National Nanotechnology Coordination Office (NNCO) provides technical and administrative support to the NSET Subcommittee and supports the subcommittee in the preparation of multi- agency planning, budget, and assessment documents, including this report. For more information on NSET, see http://www.nano.gov/html/about/nsetmembers.html . For more information on NSTC, see http://www.ostp.gov/cs/nstc . For more information on NNI, NSET and NNCO, see http://www.nano.gov . About this document This document is the report of a workshop held under the auspices of the NSET Subcommittee on February 11–13, 2004, in Arlington, Virginia. The primary purpose of the workshop was to examine trends and opportunities in nanoscale science and engineering as applied to electronic, photonic, and magnetic technologies. About the cover Cover design by Affordable Creative Services, Inc., Kathy Tresnak of Koncept, Inc., and NNCO staff.