127 research outputs found
Mesoscopic fluctuations in the shot-noise power of metals
Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Shot noise in mesoscopic systems
Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Andreev reflection in ferromagnet-superconductor junctions
Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Semiclassical theory of shot noise in mesoscopic conductors
Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe
Samenwerkingsvormen boer & burger
De agrarische sector is volop in beweging om de verbinding met de stad en de burger te maken. Een mogelijk motief hiervoor is transparantie. Het gaat hier vooral om vrijblijvend contact en eenrichtingsverkeer (boer richtingburger). In deze studie wordt geprobeerd te achterhalen hoe dat komt en wat er aan gedaan moet worden om meer initiatieven op het gebied van samenwerking van de grond te krijgen. De studie is als volgt uitgevoerd: een korte verkenning van binnenlandse en buitenlandse literatuur, interviews met stakeholders en een workshop met alle betrokkenen
Calculation of nanowire thermal conductivity using complete phonon dispersion relations
The lattice thermal conductivity of crystalline Si nanowires is calculated.
The calculation uses complete phonon dispersions, and does not require any
externally imposed frequency cutoffs. No adjustment to nanowire thermal
conductivity measurements is required. Good agreement with experimental results
for nanowires wider than 35 nm is obtained. A formulation in terms of the
transmission function is given. Also, the use of a simpler, nondispersive
"Callaway formula", is discussed from the complete dispersions perspective.Comment: 4 pages, 3 figures. Accepted in Phys. Rev.
Current noise in long diffusive SNS junctions in the incoherent MAR regime
Spectral density of current fluctuations at zero frequency is calculated for
a long diffusive SNS junction with low-resistive interfaces. At low
temperature, T << Delta, the subgap shot noise approaches linear voltage
dependence, S=(2/ 3R)(eV + 2Delta), which is the sum of the shot noise of the
normal conductor and voltage independent excess noise. This result can also be
interpreted as the 1/3-suppressed Poisson noise for the effective charge q =
e(1+2Delta/eV) transferred by incoherent multiple Andreev reflections (MAR). At
higher temperatures, anomalies of the current noise develop at the gap
subharmonics, eV = 2Delta/n. The crossover to the hot electron regime from the
MAR regime is analyzed in the limit of small applied voltages.Comment: improved version, to be published in Phys. Rev.
Shot noise of series quantum point contacts intercalating chaotic cavities
Shot noise of series quantum point contacts forming a sequence of cavities in
a two dimensional electron gas are studied theoretically and experimentally.
Noise in such a structure originates from local scattering at the point
contacts as well as from chaotic motion of the electrons in the cavities. We
found that the measured shot noise is in reasonable agreement with our
theoretical prediction taking the cavity noise into account.Comment: 4 pages, 5 figure
Nonlocal effects in the shot noise of diffusive superconductor - normal-metal systems
A cross-shaped diffusive system with two superconducting and two normal
electrodes is considered. A voltage is applied between the normal
leads. Even in the absence of average current through the superconducting
electrodes their presence increases the shot noise at the normal electrodes and
doubles it in the case of a strong coupling to the superconductors. The
nonequilibrium noise at the superconducting electrodes remains finite even in
the case of a vanishingly small transport current due to the absence of energy
transfer into the superconductors. This noise is suppressed by
electron-electron scattering at sufficiently high voltages.Comment: 4 pages, RevTeX, 2 eps figure
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