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

We present nonperturbative solutions for multievel 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 localized states, are discussed. In particular, we predict that the peak in the ratchet current as a function of the irradiation frequency splits up in two due to correlation effects.