703 research outputs found
Physics of Proximity Josephson Sensor
We study the proximity Josephson sensor (PJS) in both bolometric and
calorimetric operation and optimize it for different temperature ranges between
25 mK and a few Kelvin. We investigate how the radiation power is absorbed in
the sensor and find that the irradiated sensor is typically in a weak
nonequilibrium state. We show in detail how the proximity of the
superconductors affects the device response: for example via changes in
electron-phonon coupling and out-of-equilibrium noise. In addition, we estimate
the applicability of graphene as the absorber material.Comment: 13 pages, 11 figures, submitted to Journal of Applied Physics, v2:
Addition of a new section discussing the radiation coupling to the device,
several minor change
Resonant spin polarization and spin current in a two-dimensional electron gas
We study the spin polarization and its associated spin-Hall current due to
EDSR in disordered two-dimensional electron systems. We show that the disorder
induced damping of the resonant spin polarization can be strongly reduced by an
optimal field configuration that exploits the interference between Rashba and
Dresselhaus spin-orbit interaction. This leads to a striking enhancement of the
spin susceptibility while the spin-Hall current vanishes at the same time. We
give an interpretation of the spin current in geometrical terms which are
associated with the trajectories the polarization describes in spin space.Comment: (5 pages), updated references, corrected typo
Theory of temperature fluctuation statistics in superconductor-normal metal tunnel structures
We describe the statistics of temperature fluctuations in a SINIS structure,
where a normal metal island (N) is coupled by tunnel junctions (I) to two
superconducting leads (S). We specify conditions under which this structure
exhibits manifestly non-Gaussian fluctuations of temperature. We consider both
the Gaussian and non-Gaussian regimes of these fluctuations, and the current
fluctuations that are caused by the fluctuating temperature. We also describe a
measurement setup that could be used to observe the temperature fluctuations.Comment: 10 pages, 9 figures, final versio
Trade Effects of the Emerging Market Economies on RMD Trade and Transport Potentials for the Rhine-Main-Danube Waterway
Series: Discussion Papers of the Institute for Economic Geography and GIScienc
An -expansion for Small-World Networks
I construct a well-defined expansion in for diffusion
processes on small-world networks. The technique permits one to calculate the
average over disorder of moments of the Green's function, and is used to
calculate the average Green's function and fluctuations to first non-leading
order in , giving results which agree with numerics. This technique
is also applicable to other problems of diffusion in random media.Comment: 7 pages Europhysics style, 3 figure
Zur Entwicklung des grenzĂŒberschreitenden Warenverkehrs im Einzugsbereich der Rhein-Main-Donau-WasserstraĂe
Series: Discussion Papers of the Institute for Economic Geography and GIScienc
Kommunikationsnetze von Wissenschaftlern. Ergebnisse einer Fallstudie an Wiener UniversitÀten
Series: Discussion Papers of the Institute for Economic Geography and GIScienc
Hot electrons in low-dimensional phonon systems
A simple bulk model of electron-phonon coupling in metals has been
surprisingly successful in explaining experiments on metal films that actually
involve surface- or other low-dimensional phonons. However, by an exact
application of this standard model to a semi-infinite substrate with a free
surface, making use of the actual vibrational modes of the substrate, we show
that such agreement is fortuitous, and that the model actually predicts a
low-temperature crossover from the familiar T^5 temperature dependence to a
stronger T^6 log T scaling. Comparison with existing experiments suggests a
widespread breakdown of the standard model of electron-phonon thermalization in
metals
A semiclassical theory of the Anderson transition
We study analytically the metal-insulator transition in a disordered
conductor by combining the self-consistent theory of localization with the one
parameter scaling theory. We provide explicit expressions of the critical
exponents and the critical disorder as a function of the spatial
dimensionality, . The critical exponent controlling the divergence of
the localization length at the transition is found to be . This result confirms that the upper critical dimension is
infinity. Level statistics are investigated in detail. We show that the two
level correlation function decays exponentially and the number variance is
linear with a slope which is an increasing function of the spatial
dimensionality.Comment: 4 pages, journal versio
Contact Decision Behaviour in a Knowledge Context. A Discrete Choice Modelling Approach Using Stated Preference Data
Series: Discussion Papers of the Institute for Economic Geography and GIScienc
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