57,065 research outputs found

    Time-dependent coupled oscillator model for charged particle motion in the presence of a time varyingmagnetic field

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    The dynamics of time-dependent coupled oscillator model for the charged particle motion subjected to a time-dependent external magnetic field is investigated. We used canonical transformation approach for the classical treatment of the system, whereas unitary transformation approach is used when managing the system in the framework of quantum mechanics. For both approaches, the original system is transformed to a much more simple system that is the sum of two independent harmonic oscillators which have time-dependent frequencies. We therefore easily identified the wave functions in the transformed system with the help of invariant operator of the system. The full wave functions in the original system is derived from the inverse unitary transformation of the wave functions associated to the transformed system.Comment: 16 page

    Characterisation of the dynamical quantum state of a zero temperature Bose-Einstein condensate

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    We describe the quantum state of a Bose-Einstein condensate at zero temperature. By evaluating the Q-function we show that the ground state of Bose-Einstein condensate under the Hartree approximation is squeezed. We find that multimode Schroedinger cat states are generated as the condensate evolves in a ballistic expansion.Comment: 13 pages, 6 figure

    Fermi Surface of Cr1−x_{1-x}Vx_x across the Quantum Critical Point

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    We have measured de Haas-van Alphen oscillations of Cr1−x_{1-x}Vx_x, 0≤x≤0.050 \le x \le 0.05, at high fields for samples on both sides of the quantum critical point at xc=0.035x_c=0.035. For all samples we observe only those oscillations associated with a single small hole band with magnetic breakdown orbits of the reconstructed Fermi surface evident for x<xcx<x_c. The absence of oscillations from Fermi surface sheets most responsible for the spin density wave (SDW) in Cr for x>xcx>x_c is further evidence for strong fluctuation scattering of these charge carriers well into the paramagnetic regime. We find no significant mass enhancement of the carriers in the single observed band at any xx. An anomalous field dependence of the dHvA signal for our x=0.035x=0.035 crystal at particular orientations of the magnetic field is identified as due to magnetic breakdown that we speculate results from a field induced SDW transition at high fields.Comment: 8 pages with 7 figure

    The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC

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    We compute the rates for pp annihilation into chargino-pairs via Drell-Yan process taking into account the effects of supersymmetric soft phases, at proton-proton collider. In particular, the phase of the mu parameter gains direct accessibility via the production of dissimilar charginos. The phases of the trilinear soft masses do not have a significant effect on the cross sections.Comment: 24 pages, 7 figure
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