我们计算了两个弱相互作用介观导体的电流互相关。我们的推导是基于在Goorden和Büttiker [Phys. Rev. Lett. { \bf 99},146801(2007)]。我们包括费米海的理论,并显示如何计算运输量,特别是互相关的线索。我们研究了两个混沌量子点的零频电流互相关,并利用随机矩阵理论计算了其涨落的大小。
英文摘要:
We calculate the current cross-correlation for two weakly interacting mesoscopic conductors. Our derivation is based on the two-particle scattering matrix derived in Goorden and Büttiker [Phys. Rev. Lett. {\bf 99}, 146801 (2007)]. We include the Fermi sea in the leads into the theory and show how to calculate transport quantities and specifically cross-correlations. We focus on the zero-frequency current cross-correlation of two chaotic quantum dots and calculate the magnitude of its fluctuations with the help of Random Matrix Theory.
When combining lumped mesoscopic electronic components to form a circuit, quantum fluctuations of electrical quantities lead to a non-linear electromagnetic interaction between the components that is not generally understood. The Landauer-Büttiker formalism that is frequently used to describe non-interacting coherent mesoscopic components is not directly suited to describe such circuits since it assumes perfect voltage bias, i.e. the absence of fluctuations. Here, we show that for short coherent conductors of arbitrary transmission, the Landauer-Büttiker formalism can be extended to take into …
Comment on ``Influence Functional for Decoherence of Interacting Electrons in Disordered Conductors'' (cond-mat/0510563v1) and on related papers (cond-mat/0510556v1 and cond-mat/0510557v1)
We have investigated current-current correlations in a cross-shaped conductor made of graphene ribbons. We measured auto and cross correlations and compared them with the theoretical predictions for ideal diffusive conductors. Our data deviate from these predictions and agreement can be obtained only by adding contributions from occupation-number noise in the central region connecting the arms of the cross. Furthermore, we have determined Hanbury -- Brown and Twiss (HBT) exchange correlations in this system. Contrary to expectations for a cross-shaped diffusive system, we find finite HBT excha…
We theoretically investigate the tunneling spectroscopy of a system of two parallel one-dimensional helical conductors in the interacting, Luttinger liquid regime. We calculate the non-linear differential conductance as a function of the voltage bias between the conductors and the orbital momentum shift induced on tunneling electrons by an orthogonal magnetic field. We show that the conductance map exhibits an interference pattern which is characteristic to the interacting helical liquid. This can be contrasted with the different interference pattern from tunneling between regular Luttinger li…
Rectification by charging -- the physics of contact-induced current asymmetry in molecular conductors
我们概述了在弱相互作用自洽场(SCF)和强相互作用库仑阻塞(CB)制度下工作的分子导体中充电感应电流不对称性背后的性质不同的物理。由于平均场电位的不相等,使得超导自洽场的电导不对称性在正负偏压下发生不同的变化。一个非常不同的电流不对称性出现CB由于在相反的偏置电压的开壳层激励通道的数量不等。CB制度,占主导地位的单电荷效应,通常需要一个计算要求高的多电子或福克空间的描述。然而,我们对分子库仑阻塞测量的分析表明,许多新的签名可以用一个{更简单}的正统模型来解释,该模型涉及Fock空间激发和{ \it{hence treats the molecule as a metallic dot or an island} }的非相干总和。这也降低了复杂性的福克空间的描述只包括各种电荷配置,从而部分强调电子结构的重要性,同时保留的本质的单电荷性质的运输过程。我们最后指出,然而,列入电子结构,因此解决福克空间激发是至关重要的,在一些值得注意的例子。
We report the measurement of the third moment of current fluctuations in a short metallic wire at low temperature. The data are deduced from the statistics of voltage fluctuations across the conductor using a careful determination of environmental contributions. Our results at low bias agree very well with theoretical predictions for coherent transport with no fitting parameter. By increasing the bias voltage we explore the cross-over from elastic to inelastic transport.
Coulomb drag between nanoscale conductors is of both fundamental and practical interest. Here, we theoretically study drag in a double quantum-dot (QD) system consisting of a biased drive QD and an unbiased drag QD coupled via a direct interdot Coulomb interaction. We demonstrate that the Coulomb drag is driven by the charge fluctuations in the drive QD, and show how the properties of the associated quantum noise allow to distinguish it from, e.g., shot-noise driven drag in circuits of weakly interacting quantum conductors. In the strong-interaction regime exhibiting an orbital ("pseudospin") …
Motivated by the results of recent transport and optical conductivity studies, we propose a semi-infinite two-dimensional lattice model for interacting massive Dirac electrons in the pressurized organic conductor $α$-(BEDT-TTF)$_2$I$_3$, and address the problem of domain wall conductivity in a charge-ordered insulating phase under realistic experimental conditions. Using the extended Hubbard model at a mean field level, we present results of extensive numerical studies around the critical region of the model, reporting on the resistivity and optical conductivity calculated by means of the Naka…
In this article, we have discussed about the scattering of charge and spin in spin-resolved mesoscopic systems. We have proposed a method to generate and detect the entanglement of electronic spin and electronic orbital degrees of freedom. It is observed that in a spin-resolved mesoscopic system, all form of entanglement existing between different electronic degrees of freedom can be generated. A method to detect Bell's inequality violation in terms of zero frequency current cross-correlators has been mentioned. Further, we have also studied the effect of quantum interference between spin flip…
The electric conductivity of Dirac electrons in the organic conductor $α$-(BEDT-TTF)$_2$I$_3$ [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene] under pressure has been examined using a two-dimensional tight-binding (TB) model with both impurity and electron--phonon (e--p) scatterings. We study an anomalous temperature dependence of the conductivity, which shows a crossover from $σ_{x} < σ_{y}$ at low temperatures [region (I)] to $σ_{x} > σ_{y}$ at high temperatures [region (II)]. $σ_y$ and $σ_x$ are diagonal conductivities parallel and perpendicular to a stacking axis of molecules, respective…
We study the electronic thermal drag in two different Coulomb-coupled systems, the first one composed of two Coulomb blockaded metallic islands and the second one consisting of two parallel quantum wires. The two conductors of each system are electrically isolated and placed in the two circuits (the drive and the drag) of a four-electrode setup. The systems are biased, either by a temperature $ΔT$ or a voltage $V$ difference, on the drive circuit, while no biases are present on the drag circuit. In the case of a pair of metallic islands we use a master equation approach to determine the genera…