552 research outputs found

    On stability of the neutron rich Oxygen isotopes

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    Stability with respect to neutron emission is studied for highly neutron-excessive Oxygen isotopes in the framework of Hartree-Fock-Bogoliubov approach with Skyrme forces Sly4 and Ska. Our calculations show increase of stability around 40O.Comment: 5 pages, 3 figure

    Universal Angular Probability Distribution of Three Particles near Zero Energy Threshold

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    We study bound states of a 3--particle system in R3\mathbb{R}^3 described by the Hamiltonian H(λn)=H0+v12+λn(v13+v23)H(\lambda_n) = H_0 + v_{12} + \lambda_n (v_{13} + v_{23}), where the particle pair {1,2}\{1,2\} has a zero energy resonance and no bound states, while other particle pairs have neither bound states nor zero energy resonances. It is assumed that for a converging sequence of coupling constants λnλcr\lambda_n \to \lambda_{cr} the Hamiltonian H(λn)H(\lambda_n) has a sequence of levels with negative energies EnE_n and wave functions ψn\psi_n, where the sequence ψn\psi_n totally spreads in the sense that limnζRψn(ζ)2dζ=0\lim_{n \to \infty}\int_{|\zeta| \leq R} |\psi_n (\zeta)|^2 d\zeta = 0 for all R>0R>0. We prove that for large nn the angular probability distribution of three particles determined by ψn\psi_n approaches the universal analytical expression, which does not depend on pair--interactions. The result has applications in Efimov physics and in the physics of halo nuclei

    Using satellite radiometric and ground based lidar measurements for detection of cirrus clouds, containing ensembles of preferred oriented ice particles

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    In this paper present an example of joint analysis of the data of high-level cloud sensing with a ground based polarization lidar of Tomsk State University and satellite radiometer MODIS

    Spin-orbit Hanle effect in high-mobility quantum wells

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    We study the depolarization of optically oriented electrons in quantum wells subjected to an in-plane magnetic field and show that the Hanle curve drastically depends on the carrier mobility. In low-mobility structures, the Hanle curve is described by a Lorentzian with the width determined by the effective g-factor and the spin lifetime. In contrast, the magnetic field dependence of spin polarization in high-mobility quantum wells is nonmonotonic: The spin polarization rises with the magnetic field induction at small fields, reaches maximum and then decreases. We show that the position of the Hanle curve maximum can be used to directly measure the spin-orbit Rashba/Dresselhaus magnetic field.Comment: 4 pages, 3 figure

    Non-exponential spin relaxation in magnetic field in quantum wells with random spin-orbit coupling

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    We investigate the spin dynamics of electrons in quantum wells where the Rashba type of spin-orbit coupling is present in the form of random nanosize domains. We study the effect of magnetic field on the spin relaxation in these systems and show that the spatial randomness of spin-orbit coupling limits the minimum relaxation rate and leads to a Gaussian time-decay of spin polarization due to memory effects. In this case the relaxation becomes faster with increase of the magnetic field in contrast to the well known magnetic field suppression of spin relaxation.Comment: published version, minor change

    Measurement of ozone concentration in the lower stratosphere - upper troposphere

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    We describe an ozone lidar and consider an algorithm for retrieving the ozone concentration, taking into consideration the aerosol correction. Results of lidar measurements at wavelengths 299 and 341 nm well agree with model estimates, indicating that ozone is sensed with acceptable accuracies in the altitude range of about 6-18 km. It should be noted that the retrieved profiles of altitude distribution of ozone concentration more closely resemble those from satellite data than according to Krueger model. A lidar is developed and put into operation at Siberian Lidar Station (SLS) to measure the vertical ozone distribution (VOD) in the upper troposphere-lower stratosphere. Sensing is performed according to the method of differential absorption and scattering at wavelength pair 299/341 nm, which are respectively the first and second Stokes components of stimulated Raman scattering (SRS) conversion of the fourth harmonic of Nd:YAG laser (266 nm) in hydrogen

    Dynamic ferromagnetic proximity effect in photoexcited semiconductors

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    The spin dynamics of photoexcited carriers in semiconductors in contact with a ferromagnet is treated theoretically and compared with time-dependent Faraday rotation experiments. The long time response of the system is found to be governed by the first tens of picoseconds in which the excited plasma interacts strongly with the intrinsic interface between semiconductor and ferromagnet in spite of the existence of a Schottky barrier in equilibrium
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