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Condensed Matter papers — page 73

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Vortex states of rapidly rotating dilute Bose-Einstein condensates
We show that, in the Thomas-Fermi regime, the cores of vortices in rotating dilute Bose-Einstein condensates adjust in radius as the rotation velocity, Ω, grows, thus precluding a phase transition…
Uwe R. Fischer, Gordon BaymNov 23, 2001
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Correlation energies of inhomogeneous many-electron systems
We generalize the uniform-gas correlation energy formalism of Singwi, Tosi, Land and Sjolander to the case of an arbitrary inhomogeneous many-particle system. For jellium slabs of finite thickness…
John F. Dobson, Jun Wang, Tim GouldNov 23, 2001
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Aharonov-Casher phase and persistent current in a polyacetylene ring
We investigate a polyacetylene ring in an axially symmetric, static electric field with a modified SSH Hamiltonian of a polyacetylene chain. An effective gauge potential of the single electron…
Zhijian Li, J. Q. Liang, F. -C. PuNov 23, 2001
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Growth of a Bose-Einstein condensate: A detailed comparison of theory and experiment
We extend the earlier model of condensate growth of Davis et al [Davis MJ, Gardiner CW and Ballagh RJ 2000, Phys. Rev. A 62, 063608] to include the effect of gravity in a magnetic trap. We carry out…
MJ Davis, CW GardinerNov 23, 2001
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Surface states and their possible role in the superconductivity of MgB2
We report layer-Korringa-Kohn-Rostocker calculations for bulk and surface states as well as the corresponding angle resolved photoemission (ARPES) intensities of MgB2. Our theoretical results…
V. D. P. Servedio, S. -L. Drechsler, T. MishonovNov 22, 2001
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Mirages and enhanced magnetic interactions in quantum corrals
We develop a theory for the interactions between magnetic impurities in nanoscopic systems. The case of impurities in quantum corrals built on the (111) Cu surface is analyzed in detail. For…
A. Correa, K. Hallberg, C. A. BalseiroNov 22, 2001
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Xray-Edge Spectra From Sea-Bosons-I
The well-studied phenomenon of X-ray edge singularities is revisited using the sea-boson approach that has recently been placed on a rigorous footing. We are able to reproduce the well-known result…
Girish S. SetlurNov 22, 2001
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Nonequilibrium relaxation of Bose-Einstein condensates: Real-time equations of motion and Ward identities
We present a field-theoretical method to obtain consistently the equations of motion for small amplitude condensate perturbations in a homogeneous Bose-condensed gas directly in real time. It is…
D. Boyanovsky, S. -Y. Wang, D. -S. Lee et al.Nov 20, 2001
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Effect of Vortex Screening on the Bose Glass to Entangled Liquid Transition of Flux Lines in Superconductors
We study the phase diagram of flux lines in superconductors with columnar pins. Based on numerical exact diagonalisation simulations on small clusters, we get two phases of vortices: A low…
Ajay Nandgaonkar, D. G. Kanhere, Nandini TrivediNov 20, 2001
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Shear flow and Kelvin-Helmholtz instability in superfluids
The first realization of instabilities in the shear flow between two superfluids is examined. The interface separating the A and B phases of superfluid He-3 is magnetically stabilized. With uniform…
R. Blaauwgeers, V. B. Eltsov, G. Eska et al.Nov 19, 2001
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Disordered Systems and Logarithmic Conformal Field Theory
We review a recent development in theoretical understanding of the quenched averaged correlation functions of disordered systems and the logarithmic conformal field theory (LCFT) in d-dimensions. The…
M. Reza Rahimi TabarNov 19, 2001
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Williams and Bjerknes model with growth limitation
Williams and Bjerknes proposed a simple stochastic growth model to describe the tumor growth in the basal layer of an epithelium. In this work we generalize this model by including the possibility of…
S. C. Ferreira JuniorNov 19, 2001
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A correlated stochastic volatility model measuring leverage and other stylized facts
We present a stochastic volatility market model where volatility is correlated with return and is represented by an Ornstein-Uhlenbeck process. With this model we exactly measure the leverage effect…
Josep Perello, Jaume MasoliverNov 19, 2001
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Loop structure of the lowest Bloch band for a Bose-Einstein condensate
We investigate analytically and numerically Bloch waves for a Bose--Einstein condensate in a sinusoidal external potential. At low densities the dependence of the energy on the quasimomentum is…
Dmitri Diakonov, L. M. Jensen, C. J. Pethick et al.Nov 16, 2001
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Berry phase for ferromagnet with fractional spin
We study the double exchange model on two lattice sites with one conduction electron in the limit of an infinite Hund's interaction. While this simple problem is exactly solvable, we present an…
A. G. Abanov, Ar. AbanovNov 15, 2001
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Expansion of a Bose-Einstein Condensate in an atomic waveguide
The expansion of a Bose-Einstein condensate in an atomic waveguide is analyzed. We study different regimes of expansion, and identify a transient regime between one-dimensional and three-dimensional…
L. Plaja, L. SantosNov 15, 2001
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Ultrafast Spin Dynamics in GaAs/GaSb/InAs Heterostructures Probed by Second Harmonic Generation
We report the first application of pump-probe second harmonic generation (SHG) measurements to characterize optically-induced magnetization in non-magnetic multilayer semiconductors. In the…
Yu. D. Glinka, T. V. Shahbazyan, I. E. Perakis et al.Nov 14, 2001
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Bose-Einstein Condensates in a 1D Optical Lattice
We give an overview on current experiments on Bose-Einstein condensation (BEC) in a one-dimensional (1D) optical lattice. We introduce measurements of ground state, tunnelling and dynamical…
S. Burger, F. S. Cataliotti, F. Ferlaino et al.Nov 13, 2001
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Surface critical exponents at a uniaxial Lifshitz point
Using Monte Carlo techniques, the surface critical behaviour of three-dimensional semi-infinite ANNNI models with different surface orientations with respect to the axis of competing interactions is…
Michel PleimlingNov 13, 2001
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Topologically protected quantum bits from Josephson junction arrays
All physical implementations of quantum bits (qubits), carrying the information and computation in a putative quantum computer, have to meet the conflicting requirements of environmental decoupling…
L. B. Ioffe, M. V. Feigel'man, A. Ioselevich et al.Nov 12, 2001
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Jordan-Wigner fermions and the spin-1/2 anisotropic XY model on a square lattice
Using the two-dimensional Jordan-Wigner fermionization we calculate the thermodynamic quantities of the (spatially anisotropic) square-lattice spin-1/2 anisotropic XY (XZ) model. We compare the…
Oleg Derzhko, Johannes Richter, Taras VerkholyakNov 11, 2001
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Time dependent correlations in marine stratocumulus cloud base height records
The scaling ranges of time correlations in the cloud base height records of marine boundary layer stratocumulus are studied applying the Detrended Fluctuation Analysis statistical method. We have…
N. Kitova, K. Ivanova, M. Ausloos et al.Nov 11, 2001
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Deterministic Small-World Networks
Many real life networks, such as the World Wide Web, transportation systems, biological or social networks, achieve both a strong local clustering (nodes have many mutual neighbors) and a small…
Francesc Comellas, Michael SampelsNov 10, 2001
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3D Ising Model on Dual BCC Lattice: the Sign-Factor
The 3d Ising model on a regular cubic lattice can be expressed in terms of an SU(2) 2d fermionic model with a Z2-fluxes. We modify the model such that it is defined on the dual to a body centered…
J. Ambjorn, Sh. Khachatryan, A. SedrakyanNov 10, 2001
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Superfluidity vs Bose-Einstein condensation in a Bose gas with disorder
We investigate the phenomenon of Bose-Einstein condensation and superfluidity in a Bose gas at zero temperature with disorder. By using the Diffusion Monte-Carlo method we calculate the superfluid…
G. E. Astrakharchik, J. Boronat, J. Casulleras et al.Nov 9, 2001
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