559 research outputs found

    Study of rock experiments to measure interplanetary energetic hydrogen fluxes and hydrogen fluxes during an auroral breakup

    Get PDF
    Flux, energy spectra, and pitch angle distributions of precipitated low energy hydrogen and electrons from Nike-Tomahawk auroral hydrogen experimen

    Auroral rocket experiment 2 Final report

    Get PDF
    Detecting fluxes of energetic neutral hydrogen atoms in interplanetary medium by auroral rocket flight

    Study of an auroral zone rocket experiment Final report

    Get PDF
    Measurement of flux and energy spectra of protons, energetic particles, hydrogen atoms, and electrons in auroral zone by Nike-Tomahawk sounding rocke

    Research Notes: U.S. Regional Soybean Laboratory and University of Illinois, Urbana-Champaign

    Get PDF
    Chief\u27, a very tall Maturity Group IV variety, was used as a donor parent in backcrossing to \u27Clark\u27 to transfer Np (a gene for high phosphorus tolerance). In the field in 1963, I grew progenies from 40 selected Np F2 plants from Clark BC5 and was surprised to see 2 of the progenies uniformly very tall and 3 of them segregating approximately 1/4 tall plants. The Np gene appears to have no effect on field-grown plants in normal soils

    Intraoperative Management of Robotic-Assisted Versus Open Radical Prostatectomy

    Get PDF
    Robotic-assisted laparoscopic radical prostatectomy was found to be a shorter procedure characterized by minimal blood loss, reduced fluid requirements, and shorter hospital stay compared with traditional open procedures

    Measured quantum probability distribution functions for Brownian motion

    Full text link
    The quantum analog of the joint probability distributions describing a classical stochastic process is introduced. A prescription is given for constructing the quantum distribution associated with a sequence of measurements. For the case of quantum Brownian motion this prescription is illustrated with a number of explicit examples. In particular it is shown how the prescription can be extended in the form of a general formula for the Wigner function of a Brownian particle entangled with a heat bath.Comment: Phys. Rev. A, in pres

    Theory of Adiabatic fluctuations : third-order noise

    Full text link
    We consider the response of a dynamical system driven by external adiabatic fluctuations. Based on the `adiabatic following approximation' we have made a systematic separation of time-scales to carry out an expansion in α∣μ∣−1\alpha |\mu|^{-1}, where α\alpha is the strength of fluctuations and ∣μ∣|\mu| is the damping rate. We show that probability distribution functions obey the differential equations of motion which contain third order terms (beyond the usual Fokker-Planck terms) leading to non-Gaussian noise. The problem of adiabatic fluctuations in velocity space which is the counterpart of Brownian motion for fast fluctuations, has been solved exactly. The characteristic function and the associated probability distribution function are shown to be of stable form. The linear dissipation leads to a steady state which is stable and the variances and higher moments are shown to be finite.Comment: Plain Latex, no figures, 28 pages; to appear in J. Phys.

    Brownian Simulations and Uni-Directional Flux in Diffusion

    Full text link
    Brownian dynamics simulations require the connection of a small discrete simulation volume to large baths that are maintained at fixed concentrations and voltages. The continuum baths are connected to the simulation through interfaces, located in the baths sufficiently far from the channel. Average boundary concentrations have to be maintained at their values in the baths by injecting and removing particles at the interfaces. The particles injected into the simulation volume represent a unidirectional diffusion flux, while the outgoing particles represent the unidirectional flux in the opposite direction. The classical diffusion equation defines net diffusion flux, but not unidirectional fluxes. The stochastic formulation of classical diffusion in terms of the Wiener process leads to a Wiener path integral, which can split the net flux into unidirectional fluxes. These unidirectional fluxes are infinite, though the net flux is finite and agrees with classical theory. We find that the infinite unidirectional flux is an artifact caused by replacing the Langevin dynamics with its Smoluchowski approximation, which is classical diffusion. The Smoluchowski approximation fails on time scales shorter than the relaxation time 1/γ1/\gamma of the Langevin equation. We find the unidirectional flux (source strength) needed to maintain average boundary concentrations in a manner consistent with the physics of Brownian particles. This unidirectional flux is proportional to the concentration and inversely proportional to Δt\sqrt{\Delta t} to leading order. We develop a BD simulation that maintains fixed average boundary concentrations in a manner consistent with the actual physics of the interface and without creating spurious boundary layers

    Random paths and current fluctuations in nonequilibrium statistical mechanics

    Full text link
    An overview is given of recent advances in nonequilibrium statistical mechanics about the statistics of random paths and current fluctuations. Although statistics is carried out in space for equilibrium statistical mechanics, statistics is considered in time or spacetime for nonequilibrium systems. In this approach, relationships have been established between nonequilibrium properties such as the transport coefficients, the thermodynamic entropy production, or the affinities, and quantities characterizing the microscopic Hamiltonian dynamics and the chaos or fluctuations it may generate. This overview presents results for classical systems in the escape-rate formalism, stochastic processes, and open quantum systems

    The influence of charge detection on counting statistics

    Full text link
    We consider the counting statistics of electron transport through a double quantum dot with special emphasis on the dephasing induced by a nearby charge detector. The double dot is embedded in a dissipative enviroment, and the presence of electrons on the double dot is detected with a nearby quantum point contact. Charge transport through the double dot is governed by a non-Markovian generalized master equation. We describe how the cumulants of the current can be obtained for such problems, and investigate the difference between the dephasing mechanisms induced by the quantum point contact and the coupling to the external heat bath. Finally, we consider various open questions of relevance to future research.Comment: 15 pages, 2 figures, Contribution to 5-th International Conference on Unsolved Problems on Noise, Lyon, France, June 2-6, 200
    • …
    corecore