From integrability to conductance, impurity systems

In this work, the correlation functions of a Luttinger liquid with a cluster of impurities around an origin obtained using the Non chiral bosonization technique (NCBT) are used to study two important physical phenomena, viz., conductance and resonant tunneling. The latter is studied when the cluster consists of two impurities separated by a distance (measured in units of the Fermi wavelength). Conductance is studied both in the Kubo formalism, which relates it to current-curr...

The Landauer formula for dissipationless conductance lies at the heart of modern electronic transport, yet it remains without a clear microscopic basis. We analyze the Landauer formula microscopically, and give a straightforward quantum kinetic derivation for open systems. Some important experimental implications follow. These lie beyond the Landauer result as popularly received.

The nonlinear conductance for tunneling through an impurity in a Luttinger liquid and the nonequilibrium DC current noise are calculated exactly for low temperatures. We present a pedestrian pathway towards the exact solution which is based on analytic properties and on a duality between weak and strong backscattering. The prefactor of the T^2 enhancement is shown to be universally expressed in terms of zero temperature properties.

Conductivity in a multiband system can be divided into intra- and interband contributions, and the latter further into symmetric and antisymmetric parts. In a flat band, intraband conductivity vanishes and the antisymmetric interband contribution, proportional to the Berry curvature, corresponds to the anomalous Hall effect. We investigate whether the symmetric interband conductivity, related to the quantum metric, can be finite in the zero frequency and flat band limit. Star...

We show that the Landauer multi-terminal formula for the conductance of a nanoscale system is incomplete because it does not take into account many-body effects which cannot be treated as contributions to the single-particle transmission probabilities. We show that the physical origin of these effects is related to the viscous nature of the electron liquid, and develop a perturbative formalism, based on the time-dependent current-density-functional theory, for calculating the...

This report reviews recent progress in computing Kubo formulas for general interacting Hamiltonians. The aim is to calculate electric and thermal magneto-conductivities in strong scattering regimes where Boltzmann equation and Hall conductivity proxies exceed their validity. Three primary approaches are explained. 1. Degeneracy-projected polarization formulas for Hall-type conductivities, which substantially reduce the number of calculated current matrix elements. These exp...

Recent experiments have probed quantum dots through transport measurements in the regime where they are described by a two lead Anderson model. In this paper we develop a new method to analytically compute for the first time the corresponding transport properties. This is done by using the exact solvability of the Anderson Hamiltonian, together with a generalization of the Landauer-Buttiker approach to integrable systems. The latter requires proper identification of scatterin...

We investigate the effect of electron-electron interactions on the conductance of quasi one-dimensional systems without potential scattering. For a finite temperature or system length, the short-range interaction is not renormalized to 0, and it gives rise to a finite correction to the conductance if we calculate it using Kubo formula. We show that this correction can be absorbed into the renormalization of the chemical potential and that the properly defined conductance to b...

Using the self-consistent Born approximation to the Dirac fermions under finite-range impurity scatterings, we show that the current-current correlation function is determined by four-coupled integral equations. This is very different from the case for impurities with short-range potentials. As a test of the present approach, we calculate the electric conductivity in graphene for charged impurities with screened Coulomb potentials. The obtained conductivity at zero temperatur...

We investigate the transport properties of a quantum wire of weakly interacting fermions in the presence of a dissipative impurity. We calculate current and conductance in this system due to applied external chemical potential bias that can be measured in experimental realizations of ultracold fermions in quasi one-dimensional traps. Using a Keldysh field theory approach based on the Lindblad equation, we establish a perturbative scheme to study the effect of imbalanced reser...