101,137 research outputs found

    Virtual Compton Scattering from the Proton and the Properties of Nucleon Excited States

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    We calculate the N∗N^* contributions to the generalized polarizabilities of the proton in virtual Compton scattering. The following nucleon excitations are included: N∗(1535)N^*(1535), N∗(1650)N^*(1650), N∗(1520)N^*(1520), N∗(1700)N^*(1700), Δ(1232)\Delta(1232), Δ∗(1620)\Delta^*(1620) and Δ∗(1700)\Delta^*(1700). The relationship between nucleon structure parameters, N∗N^* properties and the generalized polarizabilities of the proton is illustrated.Comment: 13 pages of text (Latex) plus 4 figures (as uuencoded Z-compressed .tar file created by csh script uufiles

    Ground state of spin-1 Bose-Einstein condensates with spin-orbit coupling in a Zeeman field

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    We systematically investigate the weakly trapped spin-1 Bose-Einstein condensates with spin-orbit coupling in an external Zeeman field. We find that the mean-field ground state favors either a magnetized standing wave phase or plane wave phase when the strength of Zeeman field is below a critical value related to the strength of spin-orbit coupling. Zeeman field can induce the phase transition between standing wave and plane wave phases, and we determine the phase boundary analytically and numerically. The magnetization of these two phases responds to the external magnetic field in a very unique manner, the linear Zeeman effect magnetizes the standing wave phase along the direction of the magnetic field, but the quadratic one demagnetizes the plane wave phase. When the strength of Zeeman field surpasses the critical value, the system is completely polarized to a ferromagnetic state or polar state with zero momentum

    Bihamiltonian Cohomologies and Integrable Hierarchies I: A Special Case

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    We present some general results on properties of the bihamiltonian cohomologies associated to bihamiltonian structures of hydrodynamic type, and compute the third cohomology for the bihamiltonian structure of the dispersionless KdV hierarchy. The result of the computation enables us to prove the existence of bihamiltonian deformations of the dispersionless KdV hierarchy starting from any of its infinitesimal deformations.Comment: 43 pages. V2: the accepted version, to appear in Comm. Math. Phy

    Low-noise top-gate graphene transistors

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    We report results of experimental investigation of the low-frequency noise in the top-gate graphene transistors. The back-gate graphene devices were modified via addition of the top gate separated by 20 nm of HfO2 from the single-layer graphene channels. The measurements revealed low flicker noise levels with the normalized noise spectral density close to 1/f (f is the frequency) and Hooge parameter below 2 x 10^-3. The analysis of the noise spectral density dependence on the top and bottom gate biases helped us to elucidate the noise sources in these devices and develop a strategy for the electronic noise reduction. The obtained results are important for all proposed graphene applications in electronics and sensors.Comment: 9 pages, 4 figure

    Supersymmetric Harry Dym Type Equations

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    A supersymmetric version is proposed for the well known Harry Dym system. A general class super Lax operator which leads to consistent equations is considered.Comment: 4 pages, latex, no figure

    Institutions and corporate investment: Evidence from investment-implied return on capital in China

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    We assess the impact of institutions on Chinese firms' corporate investment in an investment Euler equation framework. We allow the variables measuring institutions to affect the rate at which firm managers discount future investment payoffs. Applying generalized method of moments estimators to large samples of Chinese firms, we estimate the stochastic discount rates derived from actual investment and examine how they vary across institutional variables. We document robust evidence that ownership is the primary institutional factor affecting corporate investment in China. The derived discount rate for a nonstate firm is approximately 10 percentage points higher than that of an otherwise equal state firm. State firms tend to use higher discount rates to invest after they are partially privatized. We also find that firms with higher levels of corporate governance use higher discount rates to make investment. © Copyright Michael G. Foster School of Business, University of Washington 2011.postprin
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