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Collisional-inhomogeneity-induced generation of matter-wave dark solitons

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Jul 20, 2013 07/13

by C. Wang; P. G. Kevrekidis; T. P. Horikis; D. J. Frantzeskakis

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We propose an experimentally relevant protocol for the controlled generation of matter-wave dark solitons in atomic Bose-Einstein condensates (BECs). In particular, using direct numerical simulations, we show that by switching-on a spatially inhomogeneous (step-like) change of the s-wave scattering length, it is possible to generate a controllable number of dark solitons in a quasi-one-dimensional BEC. A similar phenomenology is also found in the two-dimensional setting of...
Source: http://arxiv.org/abs/1007.2638v1

Band offsets of semiconductor heterostructures: a hybrid density functional study

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Jul 20, 2013 07/13

by Amita Wadehra; Jeremy W. Nicklas; John W. Wilkins

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We demonstrate the accuracy of the hybrid functional HSE06 for computing band offsets of semiconductor alloy heterostructures. The highlight of this study is the computation of conduction band offsets with a reliability that has eluded standard density functional theory. A high-quality special quasirandom structure models an infinite random pseudobinary alloy for constructing heterostructures along the (001) growth direction. Our excellent results for a variety of heterostructures establish...
Source: http://arxiv.org/abs/1007.2635v1

Decoherence due to elastic Rayleigh scattering

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Jul 20, 2013 07/13

by H. Uys; M. J. Biercuk; A. P. VanDevender; C. Ospelkaus; D. Meiser; R. Ozeri; J. J. Bollinger

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We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off-resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the...
Source: http://arxiv.org/abs/1007.2661v1

Bifurcation of hyperbolic planforms

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Jul 20, 2013 07/13

by Pascal Chossat; Grégory Faye; Olivier Faugeras

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Motivated by a model for the perception of textures by the visual cortex in primates, we analyse the bifurcation of periodic patterns for nonlinear equations describing the state of a system defined on the space of structure tensors, when these equations are further invariant with respect to the isometries of this space. We show that the problem reduces to a bifurcation problem in the hyperbolic plane D (Poincar\'e disc). We make use of the concept of periodic lattice in D to further reduce the...
Source: http://arxiv.org/abs/1007.2492v1

Dirichlet Process Mixtures of Generalized Linear Models

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Sep 19, 2013 09/13

by Lauren A. Hannah; David M. Blei; Warren B. Powell

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We propose Dirichlet Process mixtures of Generalized Linear Models (DP-GLM), a new method of nonparametric regression that accommodates continuous and categorical inputs, and responses that can be modeled by a generalized linear model. We prove conditions for the asymptotic unbiasedness of the DP-GLM regression mean function estimate. We also give examples for when those conditions hold, including models for compactly supported continuous distributions and a model with continuous covariates and...
Source: http://arxiv.org/abs/0909.5194v2

Quantum Hall Effect in a Holographic Model

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Sep 17, 2013 09/13

by Oren Bergman; Niko Jokela; Gilad Lifschytz; Matthew Lippert

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We consider a holographic description of a system of strongly coupled fermions in 2+1 dimensions based on a D7-brane probe in the background of D3-branes, and construct stable embeddings by turning on worldvolume fluxes. We study the system at finite temperature and charge density, and in the presence of a background magnetic field. We show that Minkowski-like embeddings that terminate above the horizon describe a family of quantum Hall states with filling fractions that are parameterized by a...
Source: http://arxiv.org/abs/1003.4965v2

Freixo de Espada À Cinta - Freixe de Espada a Cinta

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Nov 17, 2017 11/17

by Virgilio Oliveira

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Ambiencia de Freixe de Espada a Cinta. Mapa Sonoro do Rio Douro. Freixe de Espada a Cinta soundscape. Douro River Soundmap
Topics: field recording, phonography, soundscape, sound art, soundmap, radio, ephemeral, listening, radio...

Emajõe Suursoo, Tartumaa, Estonia - peipsi swamp gas

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Dec 3, 2018 12/18

by patrick tubin mcginley

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swamp gas bubbling up from the bottom of a reed bed on the edge in lake peipsi in the marshland around the inlet of the river emajõgi (with a little humming). recorded with a pair of dpa 4060's to an oade-modded fostex fr2-le.
Topics: field recording, phonography, soundscape, sound art, soundmap, radio, ephemeral, listening, radio...

Arcos_de_Valdevez, firefighters_headquarters, music_band

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Feb 21, 2013 02/13

by Carlos Santos

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Firefighters_music_band, drums, water, river, Arcos_de_Valdevez
Topics: field recording, phonography, soundscape, sound art, soundmap, radio, ephemeral, listening, radio...

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bugs

Feb 21, 2013 02/13

by keitatsu.net@gma...

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bug 愛知　豊田
Topics: field recording, phonography, soundscape, sound art, soundmap, radio, ephemeral, listening, radio...

Berlin, U8 Schönleinstr. - station cleaning

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Feb 21, 2013 02/13

by udo noll

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subway u8 schönleinstr., workers cleaning the station at night.
Topics: field recording, phonography, soundscape, sound art, soundmap, radio, ephemeral, listening, radio...

7 7.0

WUVT-FM 2010-07-15 02:00

Jan 20, 2015 01/15

by WUVT-FM

eye 7

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Topics: wuvt-fm, wuvt, airchecks, virginia tech

9 9.0

WUVT-FM 2010-07-15 22:00

Jan 20, 2015 01/15

by WUVT-FM

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Topics: wuvt-fm, wuvt, airchecks, virginia tech

7 7.0

WUVT-FM 2010-07-15 12:00

Jan 20, 2015 01/15

by WUVT-FM

eye 7

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Topics: wuvt-fm, wuvt, airchecks, virginia tech

9 9.0

WUVT-FM 2010-07-15 15:00

Jan 20, 2015 01/15

by WUVT-FM

eye 9

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Topics: wuvt-fm, wuvt, airchecks, virginia tech

Quiet sigma delta quantization, and global convergence for a class of asymmetric piecewise affine maps

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Sep 22, 2013 09/13

by Rachel Ward

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In this paper, we introduce a family of second-order sigma delta quantization schemes for analog-to-digital conversion which are `quiet' : quantization output is guaranteed to fall to zero at the onset of vanishing input. In the process, we prove that the origin is a globally attractive fixed point for the related family of asymmetrically-damped piecewise affine maps. Our proof of convergence is twofold: first, we construct a trapping set using a Lyapunov-type argument; we then take advantage...
Source: http://arxiv.org/abs/1001.2955v2

Higher-dimensional Osserman metrics with non-nilpotent Jacobi operators

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Jul 20, 2013 07/13

by E. Calvino-Louzao; E. Garcia-Rio; P. Gilkey; R. Vazquez-Lorenzo

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We exhibit Osserman metrics with non-nilpotent Jacobi operators and with non-trivial Jordan normal form in neutral signature (n,n) for any n which is at least 3. These examples admit a natural almost para-Hermitian structure and are semi para-complex Osserman with non-trivial Jordan normal form as well; they neither satisfy the third Gray identity nor are they integrable.
Source: http://arxiv.org/abs/1007.2569v1