PERSPECTIVES in QUANTUM HALL EFFECTS Novel Quantum Liquids in Low-Dimensional Semiconductor Structures
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Universal Scaling Behavior of Non-Equilibrium Phase Transitions
Universal scaling behavior of non-equilibrium phase transitions HABILITATIONSSCHRIFT der FakultÄat furÄ Naturwissenschaften der UniversitÄat Duisburg-Essen vorgelegt von Sven LubÄ eck aus Duisburg Duisburg, im Juni 2004 Zusammenfassung Kritische PhÄanomene im Nichtgleichgewicht sind seit Jahrzehnten Gegenstand inten- siver Forschungen. In Analogie zur Gleichgewichtsthermodynamik erlaubt das Konzept der UniversalitÄat, die verschiedenen NichtgleichgewichtsphasenubÄ ergÄange in unterschied- liche Klassen einzuordnen. Alle Systeme einer UniversalitÄatsklasse sind durch die glei- chen kritischen Exponenten gekennzeichnet, und die entsprechenden Skalenfunktionen werden in der NÄahe des kritischen Punktes identisch. WÄahrend aber die Exponenten zwischen verschiedenen UniversalitÄatsklassen sich hÄau¯g nur geringfugigÄ unterscheiden, weisen die Skalenfunktionen signi¯kante Unterschiede auf. Daher ermÄoglichen die uni- versellen Skalenfunktionen einerseits einen emp¯ndlichen und genauen Nachweis der UniversalitÄatsklasse eines Systems, demonstrieren aber andererseits in ubÄ erzeugender- weise die UniversalitÄat selbst. Bedauerlicherweise wird in der Literatur die Betrachtung der universellen Skalenfunktionen gegenubÄ er der Bestimmung der kritischen Exponen- ten hÄau¯g vernachlÄassigt. Im Mittelpunkt dieser Arbeit steht eine bestimmte Klasse von Nichtgleichgewichts- phasenubÄ ergÄangen, die sogenannten absorbierenden PhasenubÄ ergÄange. Absorbierende PhasenubÄ ergÄange beschreiben das kritische Verhalten von physikalischen, chemischen sowie biologischen -
Three-Dimensional Phase Transitions in Multiflavor Lattice Scalar SO (Nc) Gauge Theories
Three-dimensional phase transitions in multiflavor lattice scalar SO(Nc) gauge theories Claudio Bonati,1 Andrea Pelissetto,2 and Ettore Vicari1 1Dipartimento di Fisica dell’Universit`adi Pisa and INFN Largo Pontecorvo 3, I-56127 Pisa, Italy 2Dipartimento di Fisica dell’Universit`adi Roma Sapienza and INFN Sezione di Roma I, I-00185 Roma, Italy (Dated: January 1, 2021) We investigate the phase diagram and finite-temperature transitions of three-dimensional scalar SO(Nc) gauge theories with Nf ≥ 2 scalar flavors. These models are constructed starting from a maximally O(N)-symmetric multicomponent scalar model (N = NcNf ), whose symmetry is par- tially gauged to obtain an SO(Nc) gauge theory, with O(Nf ) or U(Nf ) global symmetry for Nc ≥ 3 or Nc = 2, respectively. These systems undergo finite-temperature transitions, where the global sym- metry is broken. Their nature is discussed using the Landau-Ginzburg-Wilson (LGW) approach, based on a gauge-invariant order parameter, and the continuum scalar SO(Nc) gauge theory. The LGW approach predicts that the transition is of first order for Nf ≥ 3. For Nf = 2 the transition is predicted to be continuous: it belongs to the O(3) vector universality class for Nc = 2 and to the XY universality class for any Nc ≥ 3. We perform numerical simulations for Nc = 3 and Nf = 2, 3. The numerical results are in agreement with the LGW predictions. I. INTRODUCTION The global O(N) symmetry is partially gauged, obtain- ing a nonabelian gauge model, in which the fields belong to the coset SN /SO(N ), where SN = SO(N)/SO(N 1) Global and local gauge symmetries play a crucial role c − in theories describing fundamental interactions [1] and is the N-dimensional sphere. -
Universal Scaling Behavior of Non-Equilibrium Phase Transitions
Universal scaling behavior of non-equilibrium phase transitions Sven L¨ubeck Theoretische Physik, Univerit¨at Duisburg-Essen, 47048 Duisburg, Germany, [email protected] December 2004 arXiv:cond-mat/0501259v1 [cond-mat.stat-mech] 11 Jan 2005 Summary Non-equilibrium critical phenomena have attracted a lot of research interest in the recent decades. Similar to equilibrium critical phenomena, the concept of universality remains the major tool to order the great variety of non-equilibrium phase transitions systematically. All systems belonging to a given universality class share the same set of critical exponents, and certain scaling functions become identical near the critical point. It is known that the scaling functions vary more widely between different uni- versality classes than the exponents. Thus, universal scaling functions offer a sensitive and accurate test for a system’s universality class. On the other hand, universal scaling functions demonstrate the robustness of a given universality class impressively. Unfor- tunately, most studies focus on the determination of the critical exponents, neglecting the universal scaling functions. In this work a particular class of non-equilibrium critical phenomena is considered, the so-called absorbing phase transitions. Absorbing phase transitions are expected to occur in physical, chemical as well as biological systems, and a detailed introduc- tion is presented. The universal scaling behavior of two different universality classes is analyzed in detail, namely the directed percolation and the Manna universality class. Especially, directed percolation is the most common universality class of absorbing phase transitions. The presented picture gallery of universal scaling functions includes steady state, dynamical as well as finite size scaling functions. -
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, -
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. -
Arxiv:1908.10990V1 [Cond-Mat.Stat-Mech] 29 Aug 2019
High-precision Monte Carlo study of several models in the three-dimensional U(1) universality class Wanwan Xu,1 Yanan Sun,1 Jian-Ping Lv,1, ∗ and Youjin Deng2, 3 1Anhui Key Laboratory of Optoelectric Materials Science and Technology, Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu, Anhui 241000, China 2Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China 3CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China We present a worm-type Monte Carlo study of several typical models in the three-dimensional (3D) U(1) universality class, which include the classical 3D XY model in the directed flow representation and its Vil- lain version, as well as the 2D quantum Bose-Hubbard (BH) model with unitary filling in the imaginary-time world-line representation. From the topology of the configurations on a torus, we sample the superfluid stiff- ness ρs and the dimensionless wrapping probability R. From the finite-size scaling analyses of ρs and of R, we determine the critical points as Tc(XY) = 2.201 844 1(5) and Tc(Villain) = 0.333 067 04(7) and (t/U)c(BH) = 0.059 729 1(8), where T is the temperature for the classical models, and t and U are respec- tively the hopping and on-site interaction strength for the BH model. The precision of our estimates improves significantly over that of the existing results. -
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 -
Crossover Between Mean-Field and Ising Critical Behavior in a Lattice-Gas Reaction-Diffusion Model Da-Jiang Liu the Ames Laboratory
Physics and Astronomy Publications Physics and Astronomy 2004 Crossover Between Mean-Field and Ising Critical Behavior in a Lattice-Gas Reaction-Diffusion Model Da-Jiang Liu The Ames Laboratory N. Pavlenko Universitat Hannover James W. Evans Iowa State University, [email protected] Follow this and additional works at: http://lib.dr.iastate.edu/physastro_pubs Part of the Chemistry Commons, and the Physics Commons The ompc lete bibliographic information for this item can be found at http://lib.dr.iastate.edu/physastro_pubs/456. For information on how to cite this item, please visit http://lib.dr.iastate.edu/howtocite.html. This Article is brought to you for free and open access by the Physics and Astronomy at Iowa State University Digital Repository. It has been accepted for inclusion in Physics and Astronomy Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Crossover Between Mean-Field and Ising Critical Behavior in a Lattice- Gas Reaction-Diffusion Model Abstract Lattice-gas models for CO oxidation can exhibit a discontinuous nonequilibrium transition between reactive and inactive states, which disappears above a critical CO-desorption rate. Using finite-size-scaling analysis, we demonstrate a crossover from Ising to mean-field behavior at the critical point, with increasing surface mobility of adsorbed CO or with decreasing system size. This behavior is elucidated by analogy with that of equilibrium Ising-type systems with long-range interactions. Keywords critical behavior, lattice-gas reaction-diffusion model, Ising, mean field Disciplines Chemistry | Physics Comments This article is published as Liu, Da-Jiang, N. -
Directed Percolation and Turbulence
Emergence of collective modes, ecological collapse and directed percolation at the laminar-turbulence transition in pipe flow Hong-Yan Shih, Tsung-Lin Hsieh, Nigel Goldenfeld University of Illinois at Urbana-Champaign Partially supported by NSF-DMR-1044901 H.-Y. Shih, T.-L. Hsieh and N. Goldenfeld, Nature Physics 12, 245 (2016) N. Goldenfeld and H.-Y. Shih, J. Stat. Phys. 167, 575-594 (2017) Deterministic classical mechanics of many particles in a box statistical mechanics Deterministic classical mechanics of infinite number of particles in a box = Navier-Stokes equations for a fluid statistical mechanics Deterministic classical mechanics of infinite number of particles in a box = Navier-Stokes equations for a fluid statistical mechanics Transitional turbulence: puffs • Reynolds’ original pipe turbulence (1883) reports on the transition Univ. of Manchester Univ. of Manchester “Flashes” of turbulence: Precision measurement of turbulent transition Q: will a puff survive to the end of the pipe? Many repetitions survival probability = P(Re, t) Hof et al., PRL 101, 214501 (2008) Pipe flow turbulence Decaying single puff metastable spatiotemporal expanding laminar puffs intermittency slugs Re 1775 2050 2500 푡−푡 − 0 Survival probability 푃 Re, 푡 = 푒 휏(Re) ) Re,t Puff P( lifetime to N-S Avila et al., (2009) Avila et al., Science 333, 192 (2011) Hof et al., PRL 101, 214501 (2008) 6 Pipe flow turbulence Decaying single puff Splitting puffs metastable spatiotemporal expanding laminar puffs intermittency slugs Re 1775 2050 2500 푡−푡 − 0 Splitting -
Block Scaling in the Directed Percolation Universality Class
OPEN ACCESS Recent citations Block scaling in the directed percolation - 25 Years of Self-organized Criticality: Numerical Detection Methods universality class R. T. James McAteer et al - The Abelian Manna model on various To cite this article: Gunnar Pruessner 2008 New J. Phys. 10 113003 lattices in one and two dimensions Hoai Nguyen Huynh et al View the article online for updates and enhancements. This content was downloaded from IP address 170.106.40.139 on 26/09/2021 at 04:54 New Journal of Physics The open–access journal for physics Block scaling in the directed percolation universality class Gunnar Pruessner1 Mathematics Institute, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK E-mail: [email protected] New Journal of Physics 10 (2008) 113003 (13pp) Received 23 July 2008 Published 7 November 2008 Online at http://www.njp.org/ doi:10.1088/1367-2630/10/11/113003 Abstract. The universal behaviour of the directed percolation universality class is well understood—both the critical scaling and the finite size scaling. This paper focuses on the block (finite size) scaling of the order parameter and its fluctuations, considering (sub-)blocks of linear size l in systems of linear size L. The scaling depends on the choice of the ensemble, as only the conditional ensemble produces the block-scaling behaviour as established in equilibrium critical phenomena. The dependence on the ensemble can be understood by an additional symmetry present in the unconditional ensemble. The unconventional scaling found in the unconditional ensemble is a reminder of the possibility that scaling functions themselves have a power-law dependence on their arguments.