1,808 research outputs found
Inelastic Interaction Corrections and Universal Relations for Full Counting Statistics
We analyze in detail the interaction correction to Full Counting Statistics
(FCS) of electron transfer in a quantum contact originating from the
electromagnetic environment surrounding the contact. The correction can be
presented as a sum of two terms, corresponding to elastic/inelastic electron
transfer. Here we primarily focus on the inelastic correction.
For our analysis, it is important to understand more general -- universal --
relations imposed on FCS only by quantum mechanics and statistics with no
regard for a concrete realization of a contact. So we derive and analyze these
relations. We reveal that for FCS the universal relations can be presented in a
form of detailed balance. We also present several useful formulas for the
cumulants.
To facilitate the experimental observation of the effect, we evaluate
cumulants of FCS at finite voltage and temperature. Several analytical results
obtained are supplemented by numerical calculations for the first three
cumulants at various transmission eigenvalues.Comment: 10 pages, 3 figure
Trapped modes in zigzag graphene nanoribbons
We study a scattering on an ultra-low potential in zigzag graphene
nanoribbon. Using mathematical framework based on the continuous Dirac model
and augumented scattering matrix, we derive a condition for the existence of a
trapped mode. We consider the threshold energies where the continuous spectrum
changes its multiplicity and show that the trapped modes may appear for
energies slightly less than a threshold and its multiplicity does not exceeds
one. We prove that trapped modes do not appear outside the threshold, provided
the potential is sufficiently small
Coupled plasmon - phonon excitations in extrinsic monolayer graphene
The existence of an acoustic plasmon in extrinsic (doped or gated) monolayer
graphene was found recently in an {\it ab initio} calculation with the frozen
lattice [M. Pisarra {\it et al.}, arXiv:1306.6273, 2013]. By the {\em fully
dynamic} density-functional perturbation theory approach, we demonstrate a
strong coupling of the acoustic plasmonic mode to lattice vibrations. Thereby,
the acoustic plasmon in graphene does not exist as an isolated excitation, but
it is rather bound into a combined plasmon-phonon mode. We show that the
coupling provides a mechanism for the {\em bidirectional} energy exchange
between the electronic and the ionic subsystems with fundamentally, as well as
practically, important implications for the lattice cooling and heating by
electrons in graphene.Comment: 5 pages, 4 figure
Lamplighter model of a random copolymer adsorption on a line
We present a model of an AB-diblock random copolymer sequential
self-packaging with local quenched interactions on a one-dimensional infinite
sticky substrate. It is assumed that the A-A and B-B contacts are favorable,
while A-B are not. The position of a newly added monomer is selected in view of
the local contact energy minimization. The model demonstrates a
self-organization behavior with the nontrivial dependence of the total energy,
(the number of unfavorable contacts), on the number of chain monomers, :
for quenched random equally probable distribution of A- and
B-monomers along the chain. The model is treated by mapping it onto the
"lamplighter" random walk and the diffusion-controlled chemical reaction of
type with the subdiffusive motion of reagents.Comment: 8 pages, 5 figure
How many quasiparticles can be in a superconductor?
Experimentally and mysteriously, the concentration of quasiparticles in a
gapped superconductor at low temperatures always by far exceeds its equilibrium
value. We study the dynamics of localized quasiparticles in superconductors
with a spatially fluctuating gap edge. The competition between phonon-induced
quasiparticle recombination and generation by a weak non-equilibrium agent
results in an upper bound for the concentration that explains the mystery.Comment: 8 pages, 8 figure
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