2,625 research outputs found
Fully Overheated Single-Electron Transistor
We consider the fully overheated single-electron transistor, where the heat
balance is determined entirely by electron transfers. We find three distinct
transport regimes corresponding to cotunneling, single-electron tunneling, and
a competition between the two. We find an anomalous sensitivity to temperature
fluctuations at the crossover between the two latter regimes that manifests in
an exceptionally large Fano factor of current noise.Comment: 6 pages, 3 figures, includes Appendi
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
The Effect of Chop Length and Additive on Silage Intake and Milk Production in Cows
Effects of reduced silage chop length on silage intake and milk production by dairy cows have been variable. Chopping of grass at harvest generally improves silage fermentation quality and consequently intake. The objective of this study was to assess the effect of chopping flail harvested silage ensiled with acid or biological additive prior to feeding on intake, milk yield and milk composition in dairy cows
Effects of Access Time to Feed and Sodium Bicarbonate in Cows Given Different Silages
Animal performance is closely related to silage intake, which might be affected by access time to feed, silage fermentation quality or using neutralising agents. The aim of this study was to assess the effects of access time to silage or addition of sodium bicarbonate on silage intake, milk yield and milk composition in diets based on restrictively fermented acid-treated or extensively fermented enzyme-treated grass silage
Statistics of temperature fluctuations in an electron system out of equilibrium
We study the statistics of the fluctuating electron temperature in a metallic
island coupled to reservoirs via resistive contacts and driven out of
equilibrium by either a temperature or voltage difference between the
reservoirs. The fluctuations of temperature are well-defined provided that the
energy relaxation rate inside the island exceeds the rate of energy exchange
with the reservoirs. We quantify these fluctuations in the regime beyond the
Gaussian approximation and elucidate their dependence on the nature of the
electronic contacts.Comment: 4 pages, 3 figure
Quantum transitions induced by the third cumulant of current fluctuations
We investigate the transitions induced by external current fluctuations on a
small probe quantum system. The rates for the transitions between the energy
states are calculated using the real-time Keldysh formalism for the density
matrix evolution. We especially detail the effects of the third cumulant of
current fluctuations inductively coupled to a quantum bit and propose a setup
for detecting the frequency-dependent third cumulant through the transitions it
induces.Comment: 4 pages, 3 figure
High-temperature surface superconductivity in topological flat-band systems
We show that the topologically protected flat band emerging on a surface of a
nodal fermionic system promotes the surface superconductivity due to an
infinitely large density of states associated with the flat band. The critical
temperature depends linearly on the pairing interaction and can be thus
considerably higher than the exponentially small bulk critical temperature. We
discuss an example of surface superconductivity in multilayered graphene with
rhombohedral stacking
Giant current fluctuations in an overheated single electron transistor
Interplay of cotunneling and single-electron tunneling in a thermally
isolated single-electron transistor (SET) leads to peculiar overheating
effects. In particular, there is an interesting crossover interval where the
competition between cotunneling and single-electron tunneling changes to the
dominance of the latter. In this interval, the current exhibits anomalous
sensitivity to the effective electron temperature of the transistor island and
its fluctuations. We present a detailed study of the current and temperature
fluctuations at this interesting point. The methods implemented allow for a
complete characterization of the distribution of the fluctuating quantities,
well beyond the Gaussian approximation. We reveal and explore the parameter
range where, for sufficiently small transistor islands, the current
fluctuations become gigantic. In this regime, the optimal value of the current,
its expectation value, and its standard deviation differ from each other by
parametrically large factors. This situation is unique for transport in
nanostructures and for electron transport in general. The origin of this
spectacular effect is the exponential sensitivity of the current to the
fluctuating effective temperature.Comment: 10 pages, 11 figure
Thermal conductance of a proximity superconductor
We study heat transport in hybrid normal metal - superconductor - normal
metal (NSN) structures. We find the thermal conductance of a short
superconducting wire to be strongly enhanced beyond the BCS value due to
inverse proximity effect. The measurements agree with a model based on the
quasiclassical theory of superconductivity in the diffusive limit. We determine
a crossover temperature below which quasiparticle heat conduction dominates
over the electron-phonon relaxation.Comment: 4+ pages, 3 figure
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