1,074 research outputs found
Realization of SU(N) Kondo effect in strong magnetic field
In this paper we suggest a realization for the SU(N) Kondo effect, using
quantum dots at strong magnetic field. We purpose using edge states of the
quantum Hall effect as pseudo spin that interact with multiple quantum dots
structures. In the suggested realization one can access each pseudo spin
separately and hence may perform a set of experiments that were impossible
until now. We focus on the realization of SU(2) and SU(3) Kondo and find a
conductivity of 3/4 quantum conductance in the SU(3) case.Comment: 5 pages, 2 figures. Including supplementary materia
Homogeneous reactions of hydrocarbons, silane, and chlorosilanes in radiofrequency plasmas at low pressures
The ion-molecule and radical-molecule mechanisms are responsible for the dissociation of hydrocarbon, silane, and chlorosilane monomers and the formation of polymerized species, respectively, in an RF plasma discharge. In a plasma containing a mixture of monomer and argon the rate-determining step for both dissociation and polymerization is governed by an ion-molecule type of interaction. Adding hydrogen or ammonia to the monomer-argon mixture transforms the rate-determining step from an ion-molecule interaction to a radical-molecule interaction for both monomer dissociation and polymerization
Radical and ion molecule mechanisms in the polymerization of hydrocarbons and chlorosilanes in RF plasmas at low pressures ( 1.0 torr)
The ion-molecule and the radical-molecule mechanisms are responsible for the dissociation of hydrocarbons, and chlorosilane monomers and the formation of polymerized species, respectively, in the plasma state of a RF discharge. In the plasma, of a mixture of monomer with Ar, the rate determining step for both dissociation and polymerization is governed by an ion-molecular type interaction. Additions of H2 or NH3 to the monomer Ar(+) mixture transforms the rate determining step from an ion-molecular interaction to a radical-molecule type interaction for both monomer dissociation and polymerization processes
Correlations between plasma variables and the deposition process of Si films from chlorosilanes in low pressure RF plasma of argon and hydrogen
The dissociation of chlorosilanes to silicon and its deposition on a solid substrate in a RF plasma of mixtures of argon and hydrogen were investigated as a function of the macrovariables of the plasma. The dissociation mechanism of chlorosilanes and HCl as well as the formation of Si in the plasma state were studied by sampling the plasma with a quadrupole mass spectrometer. Macrovariables such as pressure, net RF power input and locations in the plasma reactor strongly influence the kinetics of dissociation. The deposition process of microcrystalline silicon films and its chlorine contamination were correlated to the dissociation mechanism of chlorosilanes and HCl
A novel approach to study realistic navigations on networks
We consider navigation or search schemes on networks which are realistic in
the sense that not all search chains can be completed. We show that the
quantity , where is the average dynamic shortest distance
and the success rate of completion of a search, is a consistent measure
for the quality of a search strategy. Taking the example of realistic searches
on scale-free networks, we find that scales with the system size as
, where decreases as the searching strategy is improved.
This measure is also shown to be sensitive to the distintinguishing
characteristics of networks. In this new approach, a dynamic small world (DSW)
effect is said to exist when . We show that such a DSW indeed
exists in social networks in which the linking probability is dependent on
social distances.Comment: Text revised, references added; accepted version in Journal of
Statistical Mechanic
From non-Brownian Functionals to a Fractional Schr\"odinger Equation
We derive backward and forward fractional Schr\"odinger type of equations for
the distribution of functionals of the path of a particle undergoing anomalous
diffusion. Fractional substantial derivatives introduced by Friedrich and
co-workers [PRL {\bf 96}, 230601 (2006)] provide the correct fractional
framework for the problem at hand. In the limit of normal diffusion we recover
the Feynman-Kac treatment of Brownian functionals. For applications, we
calculate the distribution of occupation times in half space and show how
statistics of anomalous functionals is related to weak ergodicity breaking.Comment: 5 page
Enhanced shot noise in asymmetric interacting two level systems
We study a model of two interacting levels that are attached to two
electronic leads, where one of the levels is attached very weakly to the leads.
We use rate equations method to calculate the average current and the noise of
electrons transmitted through the two levels. We show that the shot noise is
enhanced due to the interactions and that the Fano factor depends on the
properties of the couplings between the levels and the leads. We study both
sequential tunneling and cotunneling processes and show that there is a range
of parameters in which the cotunneling processes affect the noise
significantly, even though most of the current is carried by sequential
tunneling processes.Comment: Published versio
Pseudospin-Resolved Transport Spectroscopy of the Kondo Effect in a Double Quantum Dot
We report measurements of the Kondo effect in a double quantum dot (DQD),
where the orbital states act as pseudospin states whose degeneracy contributes
to Kondo screening. Standard transport spectroscopy as a function of the bias
voltage on both dots shows a zero-bias peak in conductance, analogous to that
observed for spin Kondo in single dots. Breaking the orbital degeneracy splits
the Kondo resonance in the tunneling density of states above and below the
Fermi energy of the leads, with the resonances having different pseudospin
character. Using pseudospin-resolved spectroscopy, we demonstrate the
pseudospin character by observing a Kondo peak at only one sign of the bias
voltage. We show that even when the pseudospin states have very different
tunnel rates to the leads, a Kondo temperature can be consistently defined for
the DQD system.Comment: Text and supplementary information. Text: 4 pages, 5 figures.
Supplementary information: 4 pages, 4 figure
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