1,483 research outputs found
Exciting half-integer charges in a quantum point contact
We study a voltage-driven quantum point contact (QPC) strongly coupled to a
qubit. We predict pronounced observable features in the QPC current that can be
interpreted in terms of half-integer charge transfers. Our analysis is based on
the Keldysh generating functional approach and contains general results, valid
for all coherent conductors.Comment: 7 pages, 6 figure
Fully developed triplet proximity effect
We present a model for fully developed triplet proximity effect in
superconductor-ferromagnet heterostructures.
Within the circuit-theory approximation, we evaluate the Green's functions,
the density of states, and the Josephson current that depend essentially on the
magnetization configuration.Comment: 4 pages, 4 figure
Universality of the Kondo Effect in a Quantum Dot out of Equilibrium
We study the Kondo effect in a quantum dot driven out of equilibrium by an
external ac field. The Kondo effect can be probed by measuring the dc current
induced by an auxiliary dc bias applied across the dot. In the absence
of ac perturbation, the corresponding differential conductance is
known to exhibit a sharp peak at , which is the manifestation of the
Kondo effect. In the equilibrium, there exists only one energy scale, the Kondo
temperature , which controls all the low-energy physics of the system;
is some universal function of . We demonstrate that the dot out of
equilibrium is also characterized by a universal behavior: conductance
depends on the ac field only through two dimensionless parameters, which are
the frequency and the amplitude of the ac perturbation, both divided
by . We find analytically the large- and small-frequency asymptotes of the
universal dependence of on these parameters. The obtained results allow us
to predict the behavior of the conductance in the crossover regime
.Comment: 18 pages, 5 figure
Resonant tunneling of interacting electrons in a one-dimensional wire
We consider the conductance of a one-dimensional wire interrupted by a
double-barrier structure allowing for a resonant level. Using the
electron-electron interaction strength as a small parameter, we are able to
build a non-perturbative analytical theory of the conductance valid in a broad
region of temperatures and for a variety of the barrier parameters. We find
that the conductance may have a non-monotonic crossover dependence on
temperature, specific for a resonant tunneling in an interacting electron
system.Comment: 4 pages. 2 figure
Towards a robust algorithm to determine topological domains from colocalization data
One of the most important tasks in understanding the complex spatial
organization of the genome consists in extracting information about this
spatial organization, the function and structure of chromatin topological
domains from existing experimental data, in particular, from genome
colocalization (Hi-C) matrices. Here we present an algorithm allowing to reveal
the underlying hierarchical domain structure of a polymer conformation from
analyzing the modularity of colocalization matrices. We also test this
algorithm on several model polymer structures: equilibrium globules, random
fractal globules and regular fractal (Peano) conformations. We define what we
call a spectrum of cluster borders, and show that these spectra behave
strikingly differently for equilibrium and fractal conformations, allowing us
to suggest an additional criterion to identify fractal polymer conformations
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