3,863 research outputs found

    Energy transfer in binary collisions of two gyrating charged particles in a magnetic field

    Full text link
    Binary collisions of the gyrating charged particles in an external magnetic field are considered within a classical second-order perturbation theory, i.e., up to contributions which are quadratic in the binary interaction, starting from the unperturbed helical motion of the particles. The calculations are done with the help of a binary collisions treatment which is valid for any strength of the magnetic field and involves all harmonics of the particles cyclotron motion. The energy transfer is explicitly calculated for a regularized and screened potential which is both of finite range and nonsingular at the origin. The validity of the perturbation treatment is evaluated by comparing with classical trajectory Monte Carlo (CTMC) calculations which also allow to investigate the strong collisions with large energy and velocity transfer at low velocities. For large initial velocities on the other hand, only small velocity transfers occur. There the nonperturbative numerical CTMC results agree excellently with the predictions of the perturbative treatment.Comment: 12 pages, 4 figure

    Study interaction of plants and fungi in drained bed of Aral sea in Kazakhstan

    Get PDF
    The purpose of this research was the study interaction of plans and fungi in the zone of weak salinization in the DBAS

    Suspensions Thermal Noise in the LIGO Gravitational Wave Detector

    Full text link
    We present a calculation of the maximum sensitivity achievable by the LIGO Gravitational wave detector in construction, due to limiting thermal noise of its suspensions. We present a method to calculate thermal noise that allows the prediction of the suspension thermal noise in all its 6 degrees of freedom, from the energy dissipation due to the elasticity of the suspension wires. We show how this approach encompasses and explains previous ways to approximate the thermal noise limit in gravitational waver detectors. We show how this approach can be extended to more complicated suspensions to be used in future LIGO detectors.Comment: 28 pages, 13 figure

    Constraining the Nature of X-ray Cavities in Clusters and Galaxies

    Full text link
    We present results from an extensive survey of 64 cavities in the X-ray halos of clusters, groups and normal elliptical galaxies. We show that the evolution of the size of the cavities as they rise in the X-ray atmosphere is inconsistent with the standard model of adiabatic expansion of purely hydrodynamic models. We also note that the majority of the observed bubbles should have already been shredded apart by Rayleigh-Taylor and Richtmyer-Meshkov instabilities if they were of purely hydrodynamic nature. Instead we find that the data agrees much better with a model where the cavities are magnetically dominated and inflated by a current-dominated magneto-hydrodynamic jet model, recently developed by Li et al. (2006) and Nakamura et al. (2006). We conduct complex Monte-Carlo simulations of the cavity detection process including incompleteness effects to reproduce the cavity sample's characteristics. We find that the current-dominated model agrees within 1sigma, whereas the other models can be excluded at >5sigma confidence. To bring hydrodynamic models into better agreement, cavities would have to be continuously inflated. However, these assessments are dependent on our correct understanding of the detectability of cavities in X-ray atmospheres, and will await confirmation when automated cavity detection tools become available in the future. Our results have considerable impact on the energy budget associated with active galactic nucleus feedback.Comment: 21 pages, 12 figures, emulateapj, accepted for publication in ApJ, responded to referee's comments and added a new model, conclusions unchange

    Nonlocal symmetries of integrable two-field divergent evolutionary systems

    Full text link
    Nonlocal symmetries for exactly integrable two-field evolutionary systems of the third order have been computed. Differentiation of the nonlocal symmetries with respect to spatial variable gives a few nonevolutionary systems for each evolutionary system. Zero curvature representations for some new nonevolution systems are presented

    Exotic mesons and e+e- annihilation

    Get PDF
    Recent experiments at SPEAR indicate an unexpectedly large number of 1 - states in the energy range 3.9-4.4 GeV. We show how the existence of exotic cq̄c̄q mesons can account for these states as well as the rise in R and the missing ψ(3.7) decays. The width of these states does not require that they lie above the, as yet unobserved, DD̄ threshold. Predictions of the model are readily testable. © 1976 The American Physical Society

    Quantum circuits for spin and flavor degrees of freedom of quarks forming nucleons

    Full text link
    We discuss the quantum-circuit realization of the state of a nucleon in the scope of simple symmetry groups. Explicit algorithms are presented for the preparation of the state of a neutron or a proton as resulting from the composition of their quark constituents. We estimate the computational resources required for such a simulation and design a photonic network for its implementation. Moreover, we highlight that current work on three-body interactions in lattices of interacting qubits, combined with the measurement-based paradigm for quantum information processing, may also be suitable for the implementation of these nucleonic spin states.Comment: 5 pages, 2 figures, RevTeX4; Accepted for publication in Quantum Information Processin

    Comment On ``Grand Unification and Supersymmetric Threshold"

    Full text link
    Barbieri and Hall have argued that threshold effects at the scale of grand-unification wipe out predictions on the SUSY scale, M_S. Using triviality arguments we give upper bounds on ultraheavy particles, while proton stability gives lower bounds on the mass of the higgs color-triplet. We find no useful lower bound on the Σ\Sigma supermultiplet, but if the strong coupling constant is as large as recent experiments suggest, unification in the minimal SUSY SU(5) model requires that the SigmaSigma masses be 107MV\sim 10^{-7}M_V and that the color octet and weak triplet be split in mass by a factor of \sim100.Comment: 6 pages (revised

    Hidden Order and Dimerization Transition in S=2S=2 Chains

    Full text link
    We study ground state properties of the S=2S=2 quantum antiferromagnetic chain with a bond alternation H = \sum_{j} [ 1 + \delta (-1)^j ] \mbox{\boldmath $S$}_{j} \cdot \mbox{\boldmath $S$}_{j+1} by a Quantum Monte Carlo calculation. We find that the hidden Z2×Z2Z_2 \times Z_2 symmetry is broken for 0.3<δ<0.50.3 < |\delta| < 0.5 while it is unbroken in the other regions. This confirms the successive dimerization transitions first predicted by Affleck and Haldane. Our result shows that these transitions can be understood in terms of the hidden Z2×Z2Z_2 \times Z_2 symmetry breaking, as was discussed using the Valence-Bond-Solid states. Furthermore, we find that the behavior of the generalized string correlation is qualitatively very similar to that in the Valence-Bond-Solid states, including the location of zeroes as a function of the angle parameter.Comment: 3 pages (LaTex with jpsj-style files (ftp://ftp.u-tokyo.ac.jp/pub/SOCIETY/JPSJ)) and 1 Postscript figur

    Final-State Phases in Doubly-Cabibbo-Suppressed Charmed Meson Nonleptonic Decays

    Get PDF
    Cabibbo-favored nonleptonic charmed particle decays exhibit large final-state phase differences in Kˉπ\bar K \pi and Kˉπ\bar K^* \pi but not Kˉρ\bar K \rho channels. It is of interest to know the corresponding pattern of final-state phases in doubly-Cabibbo-suppressed decays, governed by the cdusˉc \to d u \bar s subprocess. An experimental program is outlined for determining such phases via measurements of rates for DKπD \to K^* \pi and K(ρ,ω,ϕ)K (\rho, \omega,\phi) channels, and determination of interference between bands in Dalitz plots. Such a program is feasible at planned high-intensity sources of charmed particles.Comment: 12 pages, LaTeX, 2 figures, to be submitted to Phys. Rev. D. Revised versio
    corecore