18,683 research outputs found

    Internal and External Fluctuation Activated Non-equilibrium Reactive Rate Process

    Full text link
    The activated rate process for non-equilibrium open systems is studied taking into account both internal and external noise fluctuations in a unified way. The probability of a particle diffusing passing over the saddle point and the rate constant together with the effective transmission coefficient are calculated via the method of reactive flux. We find that the complexity of internal noise is always harmful to the diffusion of particles. However the external modulation may be beneficial to the rate process.Comment: 10 pages, 1 figure (containing 2 subgraphs). arXiv admin note: text overlap with arXiv:cond-mat/9911028 by other author

    High accuracy results for the energy levels of the molecular ions H2+, D2+ and HD+, up to J=2

    Get PDF
    We present a nonrelativistic calculation of the rotation-vibration levels of the molecular ions H2+, D2+ and HD+, relying on the diagonalization of the exact three-body Hamiltonian. The J=2 levels are obtained with a very high accuracy of 10^{-14} a.u. (for most levels) representing an improvement by five orders of magnitude over previous calculations. The accuracy is also improved for the J=1 levels of H2+ and D2+ with respect to earlier works. Moreover, we have computed the sensitivities of the energy levels with respect to the mass ratios, allowing these levels to be used for metrological purposes.Comment: 11 page

    Exploring a Non-Minimal Sterile Neutrino Model Involving Decay at IceCube and Beyond

    Get PDF
    We study the phenomenology of neutrino decay together with neutrino oscillations in the context of eV-scale sterile neutrinos. We review the formalism of visible neutrino decay in which one of the decay products is a neutrino that potentially can be observed. We apply the formalism developed for decay to the recent sterile neutrino search performed by IceCube with TeV neutrinos. We show that for Îœ4\nu_4 lifetime τ4/m4â‰Č10−16eV−1s\tau_4/m_4 \lesssim 10^{-16} {\rm eV^{-1}s}, the interpretation of the high-energy IceCube analysis can be significantly changed.Comment: 12 pages, 7 figures. Find code at: https://github.com/arguelles/nuSQUIDSDeca

    Tracking daily fatigue fluctuations in multiple sclerosis : ecological momentary assessment provides unique insights

    Get PDF
    The preparation of this manuscript was supported by a UK Economic and Social Research Council (ESRC) PhD studentship (ES/1026266/1) awarded to DP. The study was funded by the Psychology Unit at the University of Southampton. The authors declare that they have no conflict of interest. The authors thank all participants of this study. Open access via Springer Compact Agreement.Peer reviewedPublisher PD

    Water and the Challenge of Linked Environmental Changes

    Get PDF

    Cosmological Constraints on Dissipative Models of Inflation

    Full text link
    (Abridged) We study dissipative inflation in the regime where the dissipative term takes a specific form, \Gamma=\Gamma(\phi), analyzing two models in the weak and strong dissipative regimes with a SUSY breaking potential. After developing intuition about the predictions from these models through analytic approximations, we compute the predicted cosmological observables through full numerical evolution of the equations of motion, relating the mass scale and scale of dissipation to the characteristic amplitude and shape of the primordial power spectrum. We then use Markov Chain Monte Carlo techniques to constrain a subset of the models with cosmological data from the cosmic microwave background (WMAP three-year data) and large scale structure (SDSS Luminous Red Galaxy power spectrum). We find that the posterior distributions of the dissipative parameters are highly non-Gaussian and their allowed ranges agree well with the expectations obtained using analytic approximations. In the weak regime, only the mass scale is tightly constrained; conversely, in the strong regime, only the dissipative coefficient is tightly constrained. A lower limit is seen on the inflation scale: a sub-Planckian inflaton is disfavoured by the data. In both weak and strong regimes, we reconstruct the limits on the primordial power spectrum and show that these models prefer a {\it red} spectrum, with no significant running of the index. We calculate the reheat temperature and show that the gravitino problem can be overcome with large dissipation, which in turn leads to large levels of non-Gaussianity: if dissipative inflation is to evade the gravitino problem, the predicted level of non-Gaussianity might be seen by the Planck satellite.Comment: 14 pages, 9 figures, Accepted by JCAP without text changes, References adde

    Investigation of the stall-induced shock wave (hammershock) at the inlet to the engine

    Get PDF
    The peak static pressures measured at the inlet to the engine during stall are presented for a turbojet and two turbofan engines. It is shown for one turbofan and the turbojet that the static pressure ratio across the hammershock does not exceed significantly the normal shock pressure ratio necessary to stop the flow. The second turbofan engine did not follow this rule. Possible reasons for the departure are discussed. For the two turbofan engines the influence of the stall method on the hammershock intensity was investigated. Data related to the spatial distribution of pressure in the hammershock are also presented
    • 

    corecore