Transport, optical properties and quantum ratchet effects for quantum dots and molecules coupled to Luttinger liquids

TL;DR

This paper provides exact solutions for quantum dot systems coupled to Luttinger liquids, revealing how electron interactions influence transport, noise, and optical properties, with implications for ratchet effects and photon-assisted tunneling.

Contribution

It introduces a non-perturbative approach at a special correlation point, mapping the problem to the solvable Kondo model, and explores optical and transport phenomena in coupled quantum dot structures.

Findings

Exact conductance and noise calculations at the Toulouse point.

Correlation effects cause splitting of the ratchet current peak.

Relation established between optical spectra and current noise.

Abstract

We present non-perturbative solutions for multi-level quantum dot structures coupled to interacting one-dimensional electrodes out of equilibrium. At a special correlation strength the Hamiltonian can be mapped to the Kondo problem which possesses a solvable Toulouse point, where all conductance and noise properties can be calculated exactly. Special attention is paid to the fully asymmetric setup when each dot level is coupled to only one of the leads and the electron transport through the structure is accompanied by photon absorption (emission). A relation between the optical spectra and the energy dependent current noise power is established. Experimental implications of the results, specifically for the Fano factor, the ratchet current, and field emission via localised states, are discussed. In particular, we predict that the peak in the ratchet current as function of the irradiation frequency splits up in two due to correlation effects.