9,611 research outputs found
Temporal 1/f^\alpha Fluctuations from Fractal Magnetic Fields in Black Hole Accretion Flow
Rapid fluctuation with a frequency dependence of (with ) is characteristic of radiation from black-hole objects. Its
origin remains poorly understood. We examine the three-dimensional
magnetohydrodynamical (MHD) simulation data, finding that a magnetized
accretion disk exhibits both fluctuation (with )
and a fractal magnetic structure (with the fractal dimension of ).
The fractal field configuration leads reconnection events with a variety of
released energy and of duration, thereby producing fluctuations.Comment: 5 pages, 4 figures. Accepted for publication in PASJ Letters, vol. 52
No.1 (Feb 2000
On the classical equivalence of monodromy matrices in squashed sigma model
We proceed to study the hybrid integrable structure in two-dimensional
non-linear sigma models with target space three-dimensional squashed spheres. A
quantum affine algebra and a pair of Yangian algebras are realized in the sigma
models and, according to them, there are two descriptions to describe the
classical dynamics 1) the trigonometric description and 2) the rational
description, respectively. For every description, a Lax pair is constructed and
the associated monodromy matrix is also constructed. In this paper we show the
gauge-equivalence of the monodromy matrices in the trigonometric and rational
description under a certain relation between spectral parameters and the
rescalings of sl(2) generators.Comment: 32pages, 3figures, references added, introduction and discussion
sections revise
Lunin-Maldacena backgrounds from the classical Yang-Baxter equation -- Towards the gravity/CYBE correspondence
We consider \gamma-deformations of the AdS_5xS^5 superstring as Yang-Baxter
sigma models with classical r-matrices satisfying the classical Yang-Baxter
equation (CYBE). An essential point is that the classical r-matrices are
composed of Cartan generators only and then generate abelian twists. We present
examples of the r-matrices that lead to real \gamma-deformations of the
AdS_5xS^5 superstring. Finally we discuss a possible classification of
integrable deformations and the corresponding gravity solution in terms of
solutions of CYBE. This classification may be called the gravity/CYBE
correspondence.Comment: 18 pages, no figure, LaTeX, v2:references and further clarifications
adde
The classical origin of quantum affine algebra in squashed sigma models
We consider a quantum affine algebra realized in two-dimensional non-linear
sigma models with target space three-dimensional squashed sphere. Its affine
generators are explicitly constructed and the Poisson brackets are computed.
The defining relations of quantum affine algebra in the sense of the Drinfeld
first realization are satisfied at classical level. The relation to the
Drinfeld second realization is also discussed including higher conserved
charges. Finally we comment on a semiclassical limit of quantum affine algebra
at quantum level.Comment: 25 pages, 2 figure
Integrable double deformation of the principal chiral model
© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3We define a two-parameter family of integrable deformations of the principal chiral model on an arbitrary compact group. The YangâBaxter Ï-model and the principal chiral model with a WessâZumino term both correspond to limits in which one of the two parameters vanishesPeer reviewe
Direct Minimization Approaches on Static Problems of Membranes
Within this work, direct minimization approaches on static problems of membranes are discussed. In the first half, standard direct minimization methods are discussed. Some form-finding analyses of tension structures are also illustrated as simple direct minimization approaches. In the second half, the principle of virtual works for cables, membranes, and 3-dimensional bodies are examined and they are approximated in a common way by using
Galerkin method. Finally, some examples that direct minimization approaches can solve are reported
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