We study theoretically the electronic transport through a single impurity in a repulsive Luttinger liquid (LL), and find that above a threshold voltage related to a strength of the impurity potential the DC current $\bar I$ is accompanied by coherent oscillations with frequency $f = \bar I/e$. There is an analogy with Josephson junctions: the well-known regime of power-law I-V curves in the LL corresponds to damping of the Josephson current below the critical one, while the oscillatory regime in the LL can be compared with the Josephson oscillations above the critical current.
The Noise Susceptibility of a Photo-excited Coherent Conductor
本文报道光激发导体的\emph{dynamical response of current fluctuations}理论。我们已经进行了计算的相干导体所描述的任意能量依赖的传输和任意频率。我们考虑两个实验设置，对应于不同的方式对称化当前运营商，导致不同的预测。我们的结果是在非常好的，定量协议与最近的测量。我们证明，我们已经计算的噪声的动力学响应的关键概念，涉及动态库仑阻塞，即电子-电子校正的电导由于存在的外部阻抗，量子噪声。
Coulomb Effects and Electron Transport Through a Coherent Conductor
我们分析了在库仑相互作用存在下，电子输运通过相对较短的相干导体。我们考虑到外部环境的影响，这样的导体的电流-电压特性进行评估。在我们的模型中，在大电导和低$T$的电导被抑制的一个通用的因素，这只取决于类型的导体。我们还认为，在T=0的系统"散射体+分流“可以是绝缘体或金属取决于它的总电阻是大于或小于$R_Q=h/e^2\approx 25.8$ k $Ω$。在金属相中，库仑能隙被量子涨落完全抑制。
We show that a current-carrying coherent electron conductor can be treated as effective bosonic energy reservoir involving different types of electron-hole pair excitation. For weak electron-boson coupling, hybrid energy transport between nonequilibrium electrons and bosons can be described by a Landauer-like formula. This allows for unified account of a variety of heat transport problems in hybrid electron-boson systems. As applications, we study the non-reciprocal heat transport between electrons and bosons, thermoelectric current from a cold-spot and electronic cooling of the bosons. Our un…
Interacting electrodynamics of short coherent conductors in quantum circuits
当组合集总介观电子部件以形成电路时，电学量的量子波动导致部件之间的非线性电磁相互作用，这通常不被理解。通常用于描述非相互作用相干介观元件的Landauer-Büttiker形式主义并不直接适合描述这样的电路，因为它假设完美的电压偏置，即没有波动。在这里，我们表明，对于任意传输的短相干导体，Landauer-Büttiker形式主义可以扩展到考虑类似于隧道结的量子电压波动。整个电路的电动力学，然后正式制定不顾非高斯波动。这揭示了上述非线性相互作用如何在短相干导体中操作：电压波动通过动态库仑阻塞现象引起电导的降低，但它们也修改它们的内部状态密度，从而导致传输的附加静电修改。使用这种方法，我们可以定量地解释与$R_K = h / e^2$的顺序的阻抗的量子点接触上进行的电导测量。我们的工作应该能够更好地设计具有目标特性的量子线路。
We investigate the thermoelectric response of a coherent conductor in contact with a scanning probe. Coupling to the probe has the dual effect of allowing for the controlled local injection of heat currents into the system and of inducing interference patterns in the transport coefficients. This is sufficient to generate a multiterminal thermoelectric effect even if the conductor does not effectively break electron-hole symmetry and the tip injects no charge. Considering a simple model for noninteracting electrons, we find a nonlocal thermoelectric response which is modulated by the position o…
The thermodynamic uncertainty relation (TUR) is expected to hold in nanoscale electronic conductors, when the electron transport process is quantum coherent and the transmission probability is constant (energy and voltage independent). We present measurements of the electron current and its noise in gold atomic-scale junctions and confirm the validity of the TUR for electron transport in realistic quantum coherent conductors. Furthermore, we show that it is beneficial to present the current and its noise as a TUR ratio in order to identify deviations from noninteracting-electron coherent dynam…
The concepts of Wigner time delay and Wigner-Smith matrix allow to characterize temporal aspects of a quantum scattering process. The article reviews the statistical properties of the Wigner time delay for disordered systems; the case of disorder in 1D with a chiral symmetry is discussed and the relation with exponential functionals of the Brownian motion underlined. Another approach for the analysis of time delay statistics is the random matrix approach, from which we review few results. As a pratical illustration, we briefly outline a theory of nonlinear transport and AC transport developed …
Scattering Theory of Nonlinear Thermoelectricity in Quantum Coherent Conductors
本文建立了亚微米尺度导体中弱非线性热电输运的散射理论。该理论结合了领先的非线性贡献的温度和电压偏置的充电和热电流。由于亚微米尺度导电电路的有限电容，基本的守恒定律，如规范不变性和电流守恒，需要特别注意保持。我们通过扩展Christen和Büttiker [Europhys. Lett. 35，523（1996）]的电荷和热传输耦合。在这种方式中，我们写的关系连接非线性输运系数的方式类似于莫特的关系之间的线性热电势和线性电导。我们推导出非线性输运系数必须满足的求和规则，以保持规范不变性和电流守恒。我们通过计算热机的效率和基于量子点接触和共振隧穿势垒的热电制冷器的性能系数来说明我们的理论。我们确定特别是整流效果，提高设备的性能。
How many magnetic moments periodically arranged on a metallic surface are needed to generate a coherent Kondo lattice behavior? We investigate this fundamental issue within the particle-hole symmetric Kondo lattice model using quantum Monte Carlo simulations. Extra magnetic atoms forming closed shells around the initial impurity induce a fast splitting of the Kondo resonance at the inner shells which signals the formation of composite heavy-fermion bands. The onset of the hybridization gap matches well the enhancement of antiferromagnetic spin correlations in the plane perpendicular to the app…
Periodically driven coherent conductors provide a universal platform for the development of quantum transport devices. Here, we lay down a comprehensive theory to describe the thermodynamics of these systems. We first focus on moderate thermo-electrical biases and low driving frequencies. For this linear response regime, we establish generalized Onsager-Casimir relations and an extended fluctuation-dissipation theorem. Furthermore, we derive a family of thermodynamic bounds proving that any local matter or heat current puts a non-trivial lower limit on the overall dissipation rate of a coheren…
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…
Interacting Tomonaga-Lüttinger liquid with impurity for interaction constant $K = 1/2$: Thermopower investigation, entropy variation and heat capacity densities associated with thermoelectric particle transport
University of Bouira（布依拉大学）；Higher Normal School of Bouzareah, University of Bouira（布扎雷亚高等师范学院，布依拉大学）
The electric conductivity of Dirac electrons in the organic conductor $α$-STF$_2$I$_3$ (STF = bis(ethylenedithio)diselenadithiafulvalene), which has an isostructure of ET(=bis(ethylenedithio)tetrathiafulvalene), has been theoretically studied using a two-dimensional tight-binding model in the presence of both impurity and electron-phonon (e-p) scatterings.In contrast to ET, which has a Dirac cone with almost isotropic velocity, STF provides a large anisotropy owing to a Dirac point that is close to merging. As a result, $σ_{x}$ becomes much larger than $σ_{y}$, where $σ_y$ and $σ_x$ are diagon…
Scattering theory is a standard tool for the description of transport phenomena in mesoscopic systems. Here, we provide a detailed derivation of this method for nano-scale conductors that are driven by oscillating electric or magnetic fields. Our approach is based on an extension of the conventional Lippmann-Schwinger formalism to systems with a periodically time dependent Hamiltonian. As a key result, we obtain a systematic perturbation scheme for the Floquet scattering amplitudes that describe the transition of a transport carrier through a periodically driven sample. Within a general multi-…
Low frequency resistance variations due to mobility fluctuations is one of the key factors of $1/f$ noise in metallic conductors. According to theory, such noise in a two-dimensional (2D) device can be suppressed to zero at small magnetic fields, implying important technological benefits for low noise 2D devices. In this work, we provide direct evidence of anisotropic mobility fluctuations by demonstrating a strong field-induced suppression of noise in a high-mobility graphene Corbino disk, even though the device displays only a tiny amount of $1/f$ noise inherently. The suppression of the $1/…
