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04/01/2011, 09:30
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Boris Altschuler (Columbia U.) (Columbia U.)04/01/2011, 10:00
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Thierry Giamarchi (U. of Geneva)04/01/2011, 10:50Localized spin systems, and in particular dimer systems, provide a fantastic laboratory to study the interplay between quantum effects and the interaction between excitations. Magnetic field and temperature allow an excellent control on the density of excitations and various very efficient probes such as neutrons and NMR are available. They can thus be used as ``quantum simulators'' to...Go to contribution page
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Daniel Arovas (UC San Diego) (UC San Diego)04/01/2011, 11:50I will summarize some recent developments in the study of quantum entanglement spectra. I will also discuss work performed in collaboration with R. Thomale and A. Bernevig on entanglement spectra in spin chains. Typically, bipartite entanglement entropy and spectra have been studied in the case of spatial partitions, i.e. A denotes the left half of a spin chain and B the right half,...Go to contribution page
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Ehud Altman (Weizman Institute)04/01/2011, 14:30Bosons in a one dimensional chain can form two gapped phases at integer filling, the Mott and Haldane insulators. The critical point separating these two phases is gapped out by a perturbation breaking lattice inversion symmetry. I will show that encircling the critical point adiabatically in the plane of the tuning parameter and the inversion symmetry breaking perturbation, entails...Go to contribution page
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Victor Galitski (Joint Quantum Institute and Physics Department, U. of Maryland) (U. of Maryland)04/01/2011, 15:20In this talk, I will review our recent work on a Lie-algebraic approach to various quantum-mechanical problems. The first part will be devoted to non-equilibrium driven dynamics of closed quantum systems. It will be emphasized that mathematically a non-equilibrium Hamiltonian represents a trajectory in a Lie algebra, while the evolution operator is a trajectory in a Lie group generated...Go to contribution page
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Vincent Liu (Pittsburg U)04/01/2011, 16:20In this talk, I will present some theoretical results motivated by the ongoing experiment of a lattice array of one-dimensional spin imbalanced Fermi gases with strong interaction. The system is suitable for studying dimensional crossover of the FFLO phase. I will first report for exact one dimension a breakthrough in analytically reducing the infinite coupled thermodynamic...Go to contribution page
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Alexander Balatsky (LANL)04/01/2011, 17:10Recently a new single-layer material—graphene—has been discovered. This is a material where Dirac points in the fermionic spectrum lead to very unusual properties, including transport and impurity states. I will argue that these properties are not unique to graphene and in fact are a direct consequence of the Dirac spectrum in the fermionic excitation sector. Strong similarities...Go to contribution page
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Matthias Troyer (ETH)04/01/2011, 18:15In quasi-two-dimensional systems non-abelian anyons can appear as quasiparticle excitations next to fermions and bosons. They have been proposed to appear, among other potential realizations, in certain fractional quantum Hall states. These non-Abelian anyons have non-trivial braiding statistics and can be used to realize a universal topological quantum computer. In this talk I will...Go to contribution page
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Boris Svistunov (U.Mass Amherst)05/01/2011, 10:00Monte Carlo sampling of the Feynman diagrammatic series can be used for tackling hard fermionic quantum many-body problems in the thermodynamic limit. I will introduce the technique and present illustrative results for the repulsive Hubbard model in the correlated Fermi liquid regime, as well as the results for the equation of state for the system of resonant fermions in the regime of...Go to contribution page
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Prof. Egor Babaev05/01/2011, 10:50In the recent years the interest in multicomponent superconductivity is growing due to discoveries of multiband superconducting materials and renewed experimental pursuit of the projected superconducting states of metallic hydrogen and deuterium as well as some applications in the physics of pulsars. In this talk I will overview two topics in multicomponent superconductivity. (i)...Go to contribution page
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Asle Sudbo (NTNU Trondheim) (NTNU Trondheim)05/01/2011, 12:00We consider a three-dimensional lattice $U(1) \times U(1)$ and $[U(1)]^N$ superconductors in the London limit, with individually conserved condensates. The $U(1) \times U(1)$ problem, generically, has two types of intercomponent interactions of different characters. First, the condensates are interacting via a minimal coupling to the same fluctuating gauge field. A second type of...Go to contribution page
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Victor Moshchalkov (KU Leuven) (KU Leuven)05/01/2011, 14:40
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Yoshiteru Maeno (Kyoto U) (Kyoto U.)05/01/2011, 15:30We devise a new proximity junction configuration where an /s/-wave superconductivity and the superconductivity of Sr_2 RuO_4 interfere with each other. In order to explain the observed extraordinary temperature dependence of the critical current in a Pb/Ru/Sr_2 RuO_4 junction, we propose a competition effect involving topologically distinct superconducting phases around Ru inclusions....Go to contribution page
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Beena Kalisky (Stanford U.) (Stanford)05/01/2011, 16:30We use scanning SQUID microscopy to investigate local variations in the diamagnetic susceptibility in twinned samples of two families of high temperature superconductors. In Ba(Fe1-xCox)2As2 of the pnictides we observe increased diamagnetic susceptibility on the twin boundaries in underdoped, but not overdoped, single crystals. Vortex behavior near the twin boundaries reveals that...Go to contribution page
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Ophir Auslaender (Technion - Israel Institute of Technology)05/01/2011, 17:10We use a low temperature magnetic force microscope (MFM) to study superconductors. The interaction between the magnetic tip and individual vortices allows us to both image vortices and to manipulate them. The manipulation results depend on sample thickness and on the superconducting properties. Here I concentrate on YBCO samples and on an underdoped pnictide sample. In thin films, if...Go to contribution page
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05/01/2011, 18:30
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Martin Zwierlein (MIT)06/01/2011, 10:00We study spin transport in a two-state mixture of ultracold Fermi gases near a Feshbach resonance. The strong interactions lead to extremely slow relaxation of spin currents. The relevant transport coefficients, the spin conductivity and the spin diffusion coefficient, are observed to attain universal minimal values, with the spin diffusion being given by hbar/m, where m is the atomic...Go to contribution page
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Olexei Motrunich (Caltech) (Caltech)06/01/2011, 10:50I will present our Quantum Monte Carlo studies of hard-core boson Hamiltonians with ring-only interactions on the 2D square lattice searching for a so-called Excitonic Bose Liquid (EBL). This phase, which can be viewed as a special type of "Bose metal", had eluded numerical realization since the first proposal a decade ago, as the original model showed either charge-order at...Go to contribution page
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Boris Spivak (U. of Washington) (University of Washington)06/01/2011, 11:50An overview of the measured transport properties of the two dimensional electron fluids in high mobility semiconductor devices with low electron densities is presented as well as some of the theories that have been proposed to account for them. Many features of the observations are not easily reconciled with a description based on the well understood physics of weakly interacting...Go to contribution page
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Boris Spivak (U. of Washington) (University of Washington)06/01/2011, 14:40he Pfaffian phase of electrons in the proximity of a half-filled Landau level is understood to be a p+ip superconductor of composite fermions. We consider the properties of this paired quantum Hall phase when the pairing scale is small, i.e. in the weak-coupling, BCS, limit, where the coherence length is much larger than the charge screening length. We find that, as in a Type...Go to contribution page
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James Sauls (Northwestern University) (Northwestern University)06/01/2011, 15:30Broken symmetries in bulk condensed matter systems have implications for the spec- trum of Fermionic excitations bound to surfaces and topological defects. I discuss the relationship between the broken symmetry of the ground state and the topolog- ical nature of bound states at surfaces, domain walls and topological line defects. In addition to the Fermionic spectrum, strong...Go to contribution page
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Paul Goldbart (U. of Illions Urbana Champaign) (University of Illions Urbana Champaign)06/01/2011, 16:30The self-organization of a Bose-Einstein condensate in a transversely pumped optical cavity is a process akin to crystallization: when pumped by a laser of sufficient intensity, the coupled matter and light fields evolve, spontaneously, into a spatially modulated pattern, or crystal, whose lattice structure is dictated by the geometry of the cavity. In cavities having multiple...Go to contribution page
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Charles Reichhardt (Los Alamos National Laboratory) (Los Alamos National Laboratory)07/01/2011, 10:00I will give an overview of how systems with competing interactions such as repulsion on one scale and attraction on another can generically give rise rise to bubble, stripe, clump, and other patterns. The same patterns can occur for systems with purely repulsive interactions provided there are two or more distinct length scales in the potential. I will show how these patterns can arise...Go to contribution page
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Joel Moore (Berkeley) (Berkeley)07/01/2011, 10:50The original definition of a topological insulator was as a time-reversal-symmetric insulator in which spin-orbit coupling leads to protected metallic edge or surface states. An alternate definition comes from considering the effect of a small perturbation that breaks the symmetry and gaps the surfaces; then the material can be viewed as having a quantized magnetoelectric effect. We...Go to contribution page
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Victor Gurarie (U of Colorado Boulder)07/01/2011, 11:50We develop a method to characterize interacting topological insulators with single particle Green's functions. If the interactions are switched off, it reproduces the known behavior of noninteracting topological insulators, in particular the existence of the edge states at their boundary. At the same time, the method explains why topological insulators, once the interactions are turned...Go to contribution page
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Aurel Bulgac (U. of Washington) (University of Washington)07/01/2011, 14:30Superfluidity and superconductivity are remarkable manifestations of quantum coherence at a macroscopic scale. The dynamics of superfluids has dominated the study of these systems for decades now, but a comprehensive theoretical framework is still lacking. We introduce a local extension of the time-dependent density functional theory to describe the dynamics of fermionic superfluids....Go to contribution page
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297. Multiband superconductivity at high magnetic fields and the FFLO instability in ferropnictides.Alex Gurevich (Florida State U)07/01/2011, 15:20Low carrier densities and short coherence lengths in semi-metallic ferropnictide superconductors can result in exotic behaviors at strong magnetic fields due to the interplay of multiband superconductivity, unconventional pairing symmetry and Zeeman and orbital pairbreaking. In this talk I discuss how these effects manifest themselves in the anomalous temperature dependence of the upper...Go to contribution page
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Oskar Vafek (Florida State U)07/01/2011, 16:20Many-body instabilities of the half-filled honeycomb bilayer are studied using weak-coupling renormalization group (RG) as well as strong-coupling expansion [1,2]. For spinless fermions, there are 4 independent four-fermion contact couplings. Generally, we find runaway RG flows which we associate with ordering tendencies. The broken symmetry state is typically a gapped insulator...Go to contribution page
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Walter Hofstetter (Goethe-Universität Frankfurt)07/01/2011, 17:10Cold atoms in optical lattices offer a new laboratory for the study of strong correlation phenomena.I will focus on two recent developments: i) We report the first detection of the Higgs-type amplitude mode using Bragg spectroscopy in a strongly interacting Bose condensate in an optical lattice. By the comparison of our experimental data with a spatially resolved, dynamical...Go to contribution page
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Edouard Sonin (Racah Inst. Hebrew University of Jerusalem) (Racah Inst. Hebrew University of Jerusalem)08/01/2011, 10:00Possible domain structure in p-wave superconductors with broken time-reversal symmetry is intensively discussed in literature in connection with failed experimental attempts to detect stray magnetic fields in Sr2RuO4, which were theoretical predicted for these materials. This puts in question the very idea of p-wave pairing. The lecture starts from the short overview of the...Go to contribution page
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Mihail Silaev (KTH)08/01/2011, 11:00
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Alexander Balatsky (LANL) (Los Alamos National Laboratory)Recently a new single-layer material—graphene—has been discovered. This is a material where Dirac points in the fermionic spectrum lead to very unusual properties, including transport and impurity states. I will argue that these properties are not unique to graphene and in fact are a direct consequence of the Dirac spectrum in the fermionic excitation sector. Strong similarities...Go to contribution page
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Oskar Vafek (Florida State University/Magnet Lab) (Florida State University/Magnet Lab)
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Walter Hofstetter (Goethe-Universität Frankfurt) (Goethe-Universität Frankfurt)
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Alex Gurevich (National High Magnetic Field Laboratory) (National High Magnetic Field Laboratory)
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Ophir Auslaender (Technion - Israel Institute of Technology) (Technion - Israel Institute of Technology)
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Alex Gurevich (National High Magnetic Field Laboratory) (National High Magnetic Field Laboratory)
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Boris Spivak (U. of Washington) (University of Washington)
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Martin Zwierlein (MIT) (MIT)
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Walter Hofstetter (Goethe-Universität Frankfurt)
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Victor Gurarie (U of Colorado Boulder)
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Boris Svistunov (U.Mass Amherst)
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Alex Gurevich (National High Magnetic Field Laboratory)
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James Sauls (Northwestern U.) (Northwestern University)
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