1,985 research outputs found
Full Current Statistics in the Regime of Weak Coulomb Interaction
We evaluate the full statistics of the current via a Coulomb island that is
strongly coupled to the leads. This strong coupling weakens Coulomb
interaction. We show that in this case the effects of the interaction can be
incorporated into the renormalization of transmission eigenvalues of the
scatterers that connect the island and the leads. We evaluate the Coulomb
blockade gap in the current-voltage characteristics, the value of the gap being
exponentially suppressed as compared to the classical charging energy of the
island.Comment: 4 pages, 3 figure
Coulomb Blockade due to Quantum Phase-Slips Illustrated with Devices
In order to illustrate the emergence of Coulomb blockade from coherent
quantum phase-slip processes in thin superconducting wires, we propose and
theoretically investigate two elementary setups, or "devices". The setups are
derived from Cooper-pair box and Cooper-pair transistor, so we refer to them as
QPS-box and QPS-transistor, respectively. We demonstrate that the devices
exhibit sensitivity to a charge induced by a gate electrode, this being the
main signature of Coulomb blockade. Experimental realization of these devices
will unambiguously prove the Coulomb blockade as an effect of coherence of
phase-slip processes. We analyze the emergence of discrete charging in the
limit strong phase-slips. We have found and investigated six distinct regimes
that are realized depending on the relation between three characteristic energy
scales: inductive and charging energy, and phase-slip amplitude. For
completeness, we include a brief discussion of dual Josephson-junction devices
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
Current fluctuations in composite conductors: Beyond the second cumulant
Employing the non-linear -model we analyze current fluctuations in
coherent composite conductors which contain a diffusive element in-between two
tunnel barriers. For such systems we explicitly evaluate the
frequency-dependent third current cumulant which also determines the leading
Coulomb interaction correction to shot noise. Our predictions can be directly
tested in future experiments.Comment: 6 pages, 1 figur
Coulomb interacting Dirac fermions in disordered graphene
We study interacting Dirac quasiparticles in disordered graphene and find
that an interplay between the unscreened Coulomb interactions and
pseudo-relativistic quasiparticle kinematics can be best revealed in the
ballistic regime, whereas in the diffusive limit the behavior is qualitatively
(albeit, not quantitatively) similar to that of the ordinary 2DEG with
parabolic dispersion. We calculate the quasiparticle width and density of
states that can be probed by photoemission, tunneling, and magnetization
measurements.Comment: Latex, 4 page
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