Biomedical subjects

Y V Nazarov

Publications and source records attributed to Y V Nazarov.

5 recordsLinked to original sources

PubMed2006

Using a quantum dot as a high-frequency shot noise detector.

We present the experimental realization of a quantum dot (QD) operating as a high-frequency noise detector. Current fluctuations produced in a nearby quantum point contact (QPC) ionize the QD and induce transport through excited states. The resulting transient current through the QD represents our detector signal. We investigate its dependence on the QPC transmission and voltage bias. We observe and explain a quantum threshold feature and a saturation in the detector signal. This experimental and theoretical study is relevant in understanding the backaction of a QPC used as a charge detector.

Journal Article↗

PubMed2003

Enhanced shot noise in resonant tunneling via interacting localized states.

In a variety of mesoscopic systems shot noise is seen to be suppressed in comparison with its Poisson value. In this work we observe a considerable enhancement of shot noise in the case of resonant tunneling via localized states. We present a model of correlated transport through two localized states which provides both a qualitative and a quantitative description of this effect.

Journal Article↗

PubMed2001

Full counting statistics of electron transfer between superconductors.

We present an extension of the Keldysh-Green's function method, which allows one to calculate the full distribution of transmitted particles through a mesoscopic superconductor. The method is applied to the statistics of supercurrent in short contacts. If the current is carried by Andreev bound states the distribution corresponds to switching between long trains of electrons going in opposite directions. For weak (gapless) superconductors or tunnel junctions we find that at low temperatures the distribution has negative "probabilities." Accounting for the quantum mechanical nature of the measuring device shows that these negative values can indeed be measured.

Journal Article↗

PubMed2001

Full current statistics in diffusive normal-superconductor structures.

We study the current statistics in normal diffusive conductors in contact with a superconductor. Using an extension of the Keldysh Green's function method we are able to find the full distribution of charge transfers for all temperatures and voltages. For the non-Gaussian regime, we show that the equilibrium current fluctuations are enhanced by the presence of the superconductor. We predict an enhancement of the nonequilibrium current noise for temperatures below and voltages of the order of the Thouless energy E(Th) = D/L(2). Our calculation fully accounts for the proximity effect in the normal metal and agrees with experimental data.

Journal Article↗

PubMed2001

Oscillations of Andreev states in clean ferromagnetic films.

We investigate the influence of the exchange field on the Andreev bound states in a ferromagnetic ( F) film backed on one side by a superconductor ( S). Our model accounts for diffusive reflection at the outer surface and possible backscattering at the FS interface. Phase shifting of the Andreev level by the exchange field results in an oscillatory behavior of the density of states of F as a function of the layer thickness. We show that our results agree quantitatively with recent experiments.

Journal Article↗