13,062 research outputs found

    Enhancement of variation of fundamental constants in ultracold atom and molecule systems near Feshbach resonances

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    Scattering length, which can be measured in Bose-Einstein condensate and Feshbach molecule experiments, is extremely sensitive to the variation of fundamental constants, in particular, the electron-to-proton mass ratio (m_e/m_p or m_e/Lambda_{QCD}, where Lambda_{QCD} is the QCD scale). Based on single- and two-channel scattering model, we show how the variation of the mass ratio propagates to the scattering length. Our results suggest that variation of m_e/m_p on the level of 10^{-11}~10^{-14} can be detected near a narrow magnetic or an optical Feshbach resonance by monitoring the scattering length on the 1% level. Derived formulae may also be used to estimate the isotopic shift of the scattering length

    Prosthetic glenoid fixation: lateralisation of the centre of rotation of a fixed-fulcrum total shoulder replacement is not associated with suboptimal glenoid bone formation during a functionally-relevant loading protocol

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    Prosthetic glenoid fixation: lateralisation of the centre of rotation of a fixed-fulcrum total shoulder replacement is not associated with suboptimal glenoid bone formation during a functionally-relevant loading protocol

    Lyapunov Spectra in SU(2) Lattice Gauge Theory

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    We develop a method for calculating the Lyapunov characteristic exponents of lattice gauge theories. The complete Lyapunov spectrum of SU(2) gauge theory is obtained and Kolmogorov-Sinai entropy is calculated. Rapid convergence with lattice size is found.Comment: 7pp, DUKE-TH-93-5

    Rank-ordered Multifractal Spectrum for Intermittent Fluctuations

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    We describe a new method that is both physically explicable and quantitatively accurate in describing the multifractal characteristics of intermittent events based on groupings of rank-ordered fluctuations. The generic nature of such rank-ordered spectrum leads it to a natural connection with the concept of one-parameter scaling for monofractals. We demonstrate this technique using results obtained from a 2D MHD simulation. The calculated spectrum suggests a crossover from the near Gaussian characteristics of small amplitude fluctuations to the extreme intermittent state of large rare events.Comment: 4 pages, 5 figure

    Two-Phase Annular Flow in Helical Coil Flow Channels in a Reduced Gravity Environment

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    A brief review of both single- and two-phase flow studies in curved and coiled flow geometries is first presented. Some of the complexities of two-phase liquid-vapor flow in curved and coiled geometries are discussed, and serve as an introduction to the advantages of observing such flows under a low-gravity environment. The studies proposed -- annular two-phase air-water flow in helical coil flow channels are described. Objectives of the studies are summarized

    Analytical and experimental study of stratification and liquid-ullage coupling, 1 June 1964 - 31 May 1965

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    Closed-form solution for stratification of subcooled fluids in containers subjected to heating, and for liquid-ullage vapor couplin

    Weak Hopf algebras corresponding to Cartan matrices

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    We replace the group of group-like elements of the quantized enveloping algebra Uq(g)U_q({\frak{g}}) of a finite dimensional semisimple Lie algebra g{\frak g} by some regular monoid and get the weak Hopf algebra wqd(g){\frak{w}}_q^{\sf d}({\frak g}). It is a new subclass of weak Hopf algebras but not Hopf algebras. Then we devote to constructing a basis of wqd(g){\frak{w}}_q^{\sf d}({\frak g}) and determine the group of weak Hopf algebra automorphisms of wqd(g){\frak{w}}_q^{\sf d}({\frak g}) when qq is not a root of unity.Comment: 21 page

    Dynamics of a passive sliding particle on a randomly fluctuating surface

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    We study the motion of a particle sliding under the action of an external field on a stochastically fluctuating one-dimensional Edwards-Wilkinson surface. Numerical simulations using the single-step model shows that the mean-square displacement of the sliding particle shows distinct dynamic scaling behavior, depending on whether the surface fluctuates faster or slower than the motion of the particle. When the surface fluctuations occur on a time scale much smaller than the particle motion, we find that the characteristic length scale shows anomalous diffusion with ξ(t)∼t2ϕ\xi(t)\sim t^{2\phi}, where ϕ≈0.67\phi\approx 0.67 from numerical data. On the other hand, when the particle moves faster than the surface, its dynamics is controlled by the surface fluctuations and ξ(t)∼t1/2\xi(t)\sim t^{{1/2}}. A self-consistent approximation predicts that the anomalous diffusion exponent is ϕ=2/3\phi={2/3}, in good agreement with simulation results. We also discuss the possibility of a slow cross-over towards asymptotic diffusive behavior. The probability distribution of the displacement has a Gaussian form in both the cases.Comment: 6 pages, 4 figures, error in reference corrected and new reference added, submitted to Phys. Rev.

    A new broken U(1)-symmetry in extreme type-II superconductors

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    A phase transition within the molten phase of the Abrikosov vortex system without disorder in extreme type-II superconductors is found via large-scale Monte-Carlo simulations. It involves breaking a U(1)-symmetry, and has a zero-field counterpart, unlike vortex lattice melting. Its hallmark is the loss of number-conservation of connected vortex paths threading the entire system {\it in any direction}, driving the vortex line tension to zero. This tension plays the role of a generalized ``stiffness'' of the vortex liquid, and serves as a probe of the loss of order at the transition, where a weak specific heat anomaly is found.Comment: 5 pages, 3 figure
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