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Condensed Matter papers — page 61

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On the amplification of sound (acoustic phonons) by absorption of laser radiation in cylindrical quantum wires
Based on the quantum transport equation for the electron-phonon system, the absorption coefficient of sound (acoustic phonons) by absorption of laser radiation in cylindrical quantum wires is…
Nguyen Quoc Hung, Nguyen Vu Nhan, Nguyen Quang BauApr 25, 2002
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Quasi-saddles of Liquids: Computational Study of a bulk Lennard-Jones system
Quasi-saddles or inherent saddles of the potential energy surface, U, of a liquid are defined as configurations which correspond to absolute minima of the pseudo-potential surface, W =, as…
Pooja Shah, Charusita ChakravartyApr 25, 2002
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Hamiltonians and Green's functions which interpolate between two and three dimensions
I propose to use Hamiltonians which contain two-dimensional and three-dimensional kinetic terms for the description of two-dimensional systems in physics. As a model system the evolution of…
R. DickApr 24, 2002
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Quantum Evaporation of a Bose-Einstein Condensate
We show that a Bose-Einstein condensate emits atoms, if either the condensate wave function, or the scattering length of the atoms depends strongly on time. Moreover, the emission process is coherent…
R. A. Duine, H. T. C. StoofApr 24, 2002
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1/f noise in variable range hopping conduction
A mechanism of 1/f noise due to traps formed by impurities which have no neighbors with close energies in their vicinity is studied. Such traps slowly exchange electrons with the rest of conducting…
B. I. ShklovskiiApr 23, 2002
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Chaotic Dynamics of Forest Fires
In the thermodynamic limit, a probabilistic cellular automaton can be approximated by a deterministic nonlinear map. Here we construct such a map for the forest fire problem. The construction is…
K. Malarz, S. Kaczanowska, K. KulakowskiApr 23, 2002
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Are Forest Fires Predictable?
Dynamic mean field theory is applied to the problem of forest fires. The starting point is the Monte Carlo simulation in a lattice of million cells. The statistics of the clusters is obtained by…
K. Malarz, S. Kaczanowska, K. KulakowskiApr 23, 2002
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Mobility edge scaling at semiclassical and dissipative Hall transitions
The universal anomalous diffusion scaling is obtained for the semiclassical quantum Hall transition, which has been argued to describe samples with dissipation or correlated impurities. The results…
Joel E. MooreApr 23, 2002
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Generation of new classes of integrable quantum and statistical models
A scheme based on a unifying q-deformed algebra and associated with a generalized Lax operator is proposed for generating integrable quantum and statistical models. As important applications we…
Anjan KunduApr 23, 2002
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Realization of wide electron slabs by polarization bulk doping in graded III-V nitride semiconductor alloys
We present the concept and experimental realization of polarization-induced bulk electron doping in III-V nitride semiconductors. By exploiting the large polarization charges in the III-V nitrides,…
Debdeep Jena, Sten Heikman, Daniel Green et al.Apr 23, 2002
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Electrical conductivity of lithium at megabar pressures
We report measurements of the electrical conductivity of a liquid alkali metal - lithium - at pressures up to 1.8 Mbar and fourfold compression, achieved through shock compression experiments. We…
Marina Bastea, Sorin BasteaApr 23, 2002
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Role of dipolar and exchange interactions in the positions and widths of EPR transitions for the single-molecule magnets Fe8 and Mn12
We examine quantitatively the temperature dependence of the linewidths and line shifts in electron paramagnetic resonance experiments on single crystals of the single-molecule magnets Fe8 and…
Kyungwha Park, M. A. Novotny, N. S. Dalal et al.Apr 22, 2002
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New series of integrable vertex models through a unifying approach
Applying a unifying Lax operator approach to statistical systems a new class of integrable vertex models based on quantum algebra is proposed, which exhibits a rich variety for generic q, q roots of…
Anjan KunduApr 22, 2002
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Macroscopically ordered state in exciton system
Macroscopically ordered arrays of vortices in quantum liquids, such as superconductors, He-II, and atom Bose-Einstein Condensates (BEC), demonstrate macroscopic coherence in flowing superfluids…
L. V. Butov, A. C. Gossard, D. S. ChemlaApr 22, 2002
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Intrinsic phase-decoherence of electrons by two-level systems
The fundamental problem of phase saturation of electrons in a disordered mesoscopic system at very low temperatures is addressed. The disorder in the medium has both static and dynamic components,…
Vipin Srivastava, Raishma KrishnanApr 22, 2002
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Instability of isolated triplet excitations on the Shastry-Sutherland lattice (SSL)
Configurations of singlets and triplets on the SSL have been proposed in the literature as variational ground states of the Shastry-Sutherland model at fixed magnetization M. We prove, that isolated…
A. Fledderjohann, K. -H. MuetterApr 22, 2002
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Nonequilibrium effects of anisotropic compression applied to vortex lattices in Bose-Einstein condensates
We have studied the dynamics of large vortex lattices in a dilute-gas Bose-Einstein condensate. While undisturbed lattices have a regular hexagonal structure, large-amplitude quadrupolar shape…
P. Engels, I. Coddington, P. C. Haljan et al.Apr 20, 2002
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Auger Processes in Nanosize Semiconductor Crystals
In this chapter I discuss the role that various types of Auger processes play in the linear and nonlinear optical properties of semiconductor nanocrystals.
Alexander EfrosApr 19, 2002
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Analog of Kelvin-Helmholtz instability on superfluid liquid free surface
We analyse the analog of the Kelvin-Helmholtz instability on free suface of a superfluid liquid. This instability is induced by the relative motion of superfluid and normal components of the same…
S. E. KorshunovApr 19, 2002
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Slow dynamics in the 3--D gonihedric model
We study dynamical aspects of three--dimensional gonihedric spins by using Monte--Carlo methods. The interest of this family of models (parametrized by one self-avoidance parameter κ) lies in their…
P. Dimopoulos, D. Espriu, E. Jané et al.Apr 18, 2002
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Split Instability of a Vortex in an Attractive Bose-Einstein Condensate
An attractive Bose-Einstein condensate with a vortex splits into two pieces via the quadrupole dynamical instability, which arises at a weaker strength of interaction than the monopole and the dipole…
Hiroki Saito, Masahito UedaApr 17, 2002
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Quantum Treatment of the Anderson-Hasegawa Model -- Effects of Superexchange and Polarons
We revisit the Anderson-Hasegawa double-exchange model and critically examine its exact solution when the core spins are treated quantum mechanically.We show that the quantum effects, in the presence…
Manidipa Mitra, P. A. Sreeram, Sushanta DattaguptaApr 17, 2002
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Tuning the dipolar interaction in quantum gases
We have studied the tunability of the interaction between permanent dipoles in Bose-Einstein condensates. Based on time-dependent control of the anisotropy of the dipolar interaction, we show that…
Stefano Giovanazzi, Axel Gorlitz, Tilman PfauApr 16, 2002
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Simple Dynamics for Broad Histogram Method
The purpose of this text is: 1) to clarify the foundations of the broad histogram method, stressing the conceptual differences between it and reweighting procedures in general; 2) to propose a very…
Paulo Murilo Castro de OliveiraApr 16, 2002
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Gravothermal Catastrophe and Tsallis' Generalized Entropy of Self-Gravitating Systems II. Thermodynamic Properties of Stellar Polytrope
We investigate the thermodynamic properties of stellar self-gravitating system arising from the Tsallis generalized entropy. In particular, physical interpretation of the thermodynamic instability,…
A. Taruya, M. SakagamiApr 15, 2002
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