377 research outputs found

    Accelerated Detectors and Temperature in (Anti) de Sitter Spaces

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    We show, in complete accord with the usual Rindler picture, that detectors with constant acceleration aa in de Sitter (dS) and Anti de Sitter (AdS) spaces with cosmological constants Λ\Lambda measure temperatures 2πT=(Λ/3+a2)1/2a52\pi T=(\Lambda/3+a^{2})^{1/2}\equiv a_{5}, the detector "5-acceleration" in the embedding flat 5-space. For dS, this recovers a known result; in AdS, where Λ\Lambda is negative, the temperature is well defined down to the critical value a5=0a_{5}=0, again in accord with the underlying kinematics. The existence of a thermal spectrum is also demonstrated for a variety of candidate wave functions in AdS backgrounds.Comment: Latex +2 Fi

    Thermalization of the system "3He-aerogel" at 1.5 K

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    At the present work we propose a new method for studying the processes of thermodynamic equilibrium setting in the adsorbed 3He film in a porous media. By this method we have studied the thermalization of the adsorbed 3He on the silica aerogel surface at the temperature 1.5 K. The process of the thermodynamic equilibrium setting was controlled by measuring of the pressure in the experimental cell, the amplitude of the NMR signal and the time of the nuclear spin-spin and spin-lattice relaxation times of an adsorbed 3He. The thermodynamic equilibrium setting in the system "adsorbed helium-3 - aerogel" has the characteristic time 26 min.Comment: 4 figure

    Boundary resistance in magnetic multilayers

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    Quasiclassical boundary conditions for electrochemical potentials at the interface between diffusive ferromagnetic and non-magnetic metals are derived for the first time. An expression for the boundary resistance accurately accounts for the momentum conservation law as well as essential gradients of the chemical potentials. Conditions are established at which spin-asymmetry of the boundary resistance has positive or negative sign. Dependence of the spin asymmetry and the absolute value of the boundary resistance on the exchange splitting of the conduction band opens up new possibility to estimate spin polarization of the conduction band of ferromagnetic metals. Consistency of the theory is checked on existing experimental data.Comment: 8 pages, 3 figures, designed using IOPART styl
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