Weak-Light Nonlinearity Using a Dark State in Coupled Quantum Dots

TL;DR

This paper presents a scheme to induce weak-light nonlinearity in coupled quantum dots by utilizing locality and dissipation, enabling the preparation of a two-exciton NOON state with very weak light.

Contribution

It introduces a novel approach leveraging locality and dissipation in an auxiliary system to achieve weak-light nonlinearity and generate two-photon states in quantum dots.

Findings

Weak-light nonlinearity achieved in coupled quantum dots.

Preparation of a dipole-forbidden two-exciton NOON state.

Effective two-photon processes via dissipation and locality.

Abstract

We propose a scheme to induce weak-light nonlinearity in a double quantum dot. The scheme positively utilizes locality and dissipation of an external auxiliary system. As a plausible setup, we consider a complex system in which a localized plasmon field from a metallic nanotip couples with only one of the coupled quantum dots. The perturbative calculation with respect to the light intensity shows that, even by a sufficiently weak light, a dipole-forbidden two-exciton NOON state is prepared as the steady state. This result can be explained by combining the two factors: decoherence-induced quantum state preparation and two-photon resonance. The present work implies that the positive usage of both the locality and the dissipation in the external auxiliary system is promising for inducing two-photon processes effectively, and provides one guideline to weak-light nonlinearities.