1,049 research outputs found

    Statistical Mechanics of Charged Particles in Einstein-Maxwell-Scalar Theory

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    We consider an NN-body system of charged particle coupled to gravitational, electromagnetic, and scalar fields. The metric on moduli space for the system can be considered if a relation among the charges and mass is satisfied, which includes the BPS relation for monopoles and the extreme condition for charged black holes. Using the metric on moduli space in the long distance approximation, we study the statistical mechanics of the charged particles at low velocities. The partition function is evaluated as the leading order of the large dd expansion, where dd is the spatial dimension of the system and will be substituted finally as d=3d=3.Comment: 11 pages, RevTeX3.

    Forced Topological Nontrivial Field Configurations

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    The motion of a one-dimensional kink and its energy losses are considered as a model of interaction of nontrivial topological field configurations with external fields. The approach is based on the calculation of the zero modes excitation probability in the external field. We study in the same way the interaction of the t'Hooft-Polyakov monopole with weak external fields. The basic idea is to treat the excitation of a monopole zero mode as the monopole displacement. The excitation is found perturbatively. As an example we consider the interaction of the t'Hooft-Polyakov monopole with an external uniform magnetic field.Comment: 18 pages, 3 Postscript figures, RevTe

    New Integrable Sectors in Skyrme and 4-dimensional CP^n Model

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    The application of a weak integrability concept to the Skyrme and CPnCP^n models in 4 dimensions is investigated. A new integrable subsystem of the Skyrme model, allowing also for non-holomorphic solutions, is derived. This procedure can be applied to the massive Skyrme model, as well. Moreover, an example of a family of chiral Lagrangians providing exact, finite energy Skyrme-like solitons with arbitrary value of the topological charge, is given. In the case of CPnCP^n models a tower of integrable subsystems is obtained. In particular, in (2+1) dimensions a one-to-one correspondence between the standard integrable submodel and the BPS sector is proved. Additionally, it is shown that weak integrable submodels allow also for non-BPS solutions. Geometric as well as algebraic interpretations of the integrability conditions are also given.Comment: 23 page

    Conservation Laws in a First Order Dynamical System of Vortices

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    Gauge invariant conservation laws for the linear and angular momenta are studied in a certain 2+1 dimensional first order dynamical model of vortices in superconductivity. In analogy with fluid vortices it is possible to express the linear and angular momenta as low moments of vorticity. The conservation laws are compared with those obtained in the moduli space approximation for vortex dynamics.Comment: LaTex file, 16 page

    Symptom profiles of psychiatric disorders based on graded disease classes: an illustration using data from the WHO International Pilot Study of Schizophrenia

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    The Grade of Membership (GoM) model is a classification procedure which allows a person to be a member of more than one diagnostic class. It simultaneously quantifies the degrees of membership in classes while generating the discrete symptom profiles or ‘pure types' describing classes. The model was applied to the symptomatology, history, and follow-up of 1065 cases in the WHO International Pilot Study of Schizophrenia. The model produced an eight diagnostic class or ‘pure type' solution, of which five were related to the diagnostic concepts of schizophrenia and paranoid disorder, two types were affective disorders, and one asymptomatic type. A subtype of paranoid schizophreniform disorder found primarily in developing countries was identified. There was a strong association between pure types and the original clinical and computer generated (CATEGO) diagnoses. A GoM based psychiatric classification might more clearly identify core disease processes than conventional classification models by filtering the confounding effects of individual heterogeneity from pure type definition

    Algorithms and literate programs for weighted low-rank approximation with missing data

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    Linear models identification from data with missing values is posed as a weighted low-rank approximation problem with weights related to the missing values equal to zero. Alternating projections and variable projections methods for solving the resulting problem are outlined and implemented in a literate programming style, using Matlab/Octave's scripting language. The methods are evaluated on synthetic data and real data from the MovieLens data sets

    Radiation Damping of a BPS Monopole; an Implication to S-duality

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    The radiation reaction of a BPS monopole in the presence of incident electromagnetic waves as well as massless Higgs waves is analyzed classically. The reactive forces are compared to those of WW boson that is interpreted as a dual partner of the BPS monopole. It is shown that the damping of acceleration is dual to each other, while in the case of finite size effects the duality is broken explicitly. Their implications on the duality are discussed.Comment: 20 pages, uses revtex, changes in reference

    On Axially Symmetric Solutions in the Electroweak Theory

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    We present the general ansatz, the energy density and the Chern-Simons charge for static axially symmetric configurations in the bosonic sector of the electroweak theory. Containing the sphaleron, the multisphalerons and the sphaleron-antisphaleron pair at finite mixing angle, the ansatz further allows the construction of the sphaleron and multisphaleron barriers and of the bisphalerons at finite mixing angle. We conjecture that further solutions exist.Comment: 17 pages, latex, THU-94/0

    Non-existence of Skyrmion-Skyrmion and Skyrmion-anti-Skyrmion static equilibria

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    We consider classical static Skyrmion-anti-Skyrmion and Skyrmion-Skyrmion configurations, symmetric with respect to a reflection plane, or symmetric up to a GG-parity transformation respectively. We show that the stress tensor component completely normal to the reflection plane, and hence its integral over the plane, is negative definite or positive definite respectively. Classical Skyrmions always repel classical Skyrmions and classical Skyrmions always attract classical anti-Skyrmions and thus no static equilibrium, whether stable or unstable, is possible in either case. No other symmetry assumption is made and so our results also apply to multi-Skyrmion configurations. Our results are consistent with existing analyses of Skyrmion forces at large separation, and with numerical results on Skymion-anti-Skyrmion configurations in the literature which admit a different reflection symmetry. They also hold for the massive Skyrme model. We also point out that reflection symmetric self-gravitating Skyrmions or black holes with Skyrmion hair cannot rest in symmetric equilibrium with self-gravitating anti-Skyrmions.Comment: v2 Typos corrected, refs added. v3 Journal versio
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