Transport through a quantum dot with excitonic dot-lead coupling

We study the effect of a Coulombic dot-lead interaction on transport through a quantum dot hybridized to two Luttinger-liquid leads.\footnote{F. Elste, D. R. Reichman, and A. J. Millis, arXiv:1010.2251} A bosonization approach is applied to treat the interaction between charge fluctuations on the dot and the dynamically generated image charge in the leads.\footnote{F. Elste, D. R. Reichman, and A. J. Millis, Phys.\ Rev.\ B \textbf{81}, 205413 (2010)} The nonequilibrium distribution function of the dot and the tunneling current are computed within a master-equation approach. Particular attention is paid to two situations: (i) a quantum dot placed between two leads such that it cuts the Luttinger liquid into two semi-infinite quantum wires; (ii) a quantum dot side-hybridized to two parallel infinite quantum wires. The presence of the excitonic dot-lead coupling is found to enhance transport in the vicinity of the Coulomb-blockade threshold. This behavior is in contrast to the usual power-law suppression of electronic tunneling which is found if this interaction is ignored.