287,112 research outputs found

    Diffusion-convection function of cosmic rays

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    The fundamental properties and some numerical results of the solution of the diffusion equation of an impulsive cosmic-ray point source in an uniform, unbounded and spherically symmetrical moving medium is presented. The diffusion-convection(D-C) function is an elementary composite function of the solution of the D-C equation for the particles injected impulsively from a diffusive point source into the medium. It is the analytic solution derived by the dimensional method for the propagation equation of solar cosmic rays in the heliosphere, i.e. the interplanetary space. Because of the introduction of convection effect of solar wind, a nonhomogeneous term appears in the propagation equation, it is difficult to express its solution in terms of the ordinary special functions. The research made so far has led to a solution containing only the first order approximation of the convection effect

    Baryons as Solitons in Three Dimensional Quantum Chromodynamics

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    We show that baryons of three dimensional Quantum Chromodynamics can be understood as solitons of its effective lagrangian. In the parity preserving phase we study, these baryons are fermions for odd NcN_c and bosons for even NcN_c, never anyons. We quantize the collective variables of the solitons and there by calculate the flavor quantum numbers, magnetic moments and mass splittings of the baryon. The flavor quantum numbers are in agreement with naive quark model for the low lying states. The magnetic moments and mass splittings are smaller in the soliton model by a factor of logFπNcmπ\log {F_\pi\over N_c m_\pi}. We also show that there is a dibaryon solution that is an analogue of the deuteron. These solitons can describe defects in a quantum anti--ferromagnet.Comment: 22 pages + 4 figures (figures not included, postscript files available upon request

    The Effective Lagrangian of Three Dimensional Quantum Chromodynamics

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    We consider the low energy limit of three dimensional Quantum Chromodynamics with an even number of flavors. We show that Parity is not spontaneously broken, but the global (flavor) symmetry is spontaneously broken. The low energy effective lagrangian is a nonlinear sigma model on the Grassmannian. Some Chern--Simons terms are necessary in the lagrangian to realize the discrete symmetries correctly. We consider also another parametrization of the low energy sector which leads to a three dimensional analogue of the Wess--Zumino--Witten--Novikov model. Since three dimensional QCD is believed to be a model for quantum anti--ferromagnetism, our effective lagrangian can describe their long wavelength excitations (spin waves).Comment: 18 page

    Three Dimensional Quantum Chromodynamics

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    The subject of this talk was the review of our study of three (2+12+1) dimensional Quantum Chromodynamics. In our previous works, we showed the existence of a phase where parity is unbroken and the flavor group U(2n)U(2n) is broken to a subgroup U(n)×U(n)U(n)\times U(n). We derived the low energy effective action for the theory and showed that it has solitonic excitations with Fermi statistic, to be identified with the three dimensional ``baryon''. Finally, we studied the current algebra for this effective action and we found a co-homologically non trivial generalization of Kac-Moody algebras to three dimensions.Comment: 7 pages, Plain TEX, talk presented by S.G. Rajeev at the XXVI INTERNATIONAL CONFERENCE ON HIGH ENERGY PHYSICS, DALLAS TX AUG. 199

    High-voltage spark carbon-fiber sticky-tape data analyzer

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    An efficient method for detecting carbon fibers collected on a stick tape monitor was developed. The fibers were released from a simulated crash fire situation containing carbon fiber composite material. The method utilized the ability of the fiber to initiate a spark across a set of alternately biased high voltage electrodes to electronically count the number of fiber fragments collected on the tape. It was found that the spark, which contains high energy and is of very short duration, is capable of partially damaging or consuming the fiber fragments. It also creates a mechanical disturbance which ejects the fiber from the grid. Both characteristics were helpful in establishing a single discharge pulse for each fiber segment

    Cryptanalyzing a discrete-time chaos synchronization secure communication system

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    This paper describes the security weakness of a recently proposed secure communication method based on discrete-time chaos synchronization. We show that the security is compromised even without precise knowledge of the chaotic system used. We also make many suggestions to improve its security in future versions.Comment: 11 pages, 3 figures, latex forma

    Quantum steering of electron wave function in an InAs Y-branch switch

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    We report experiments on gated Y-branch switches made from InAs ballistic electron wave guides. We demonstrate that gating modifies the electron wave functions as well as their interference pattern, causing the anti-correlated, oscillatory transconductances. Such previously unexpected phenomenon provides evidence of steering the electron wave function in a multi-channel transistor structure.Comment: 15 pages, including 3 figure
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