Nanoshell-mediated robust entanglement between coupled quantum dots

Abstract

The exact entanglement dynamics in a hybrid structure consisting of two quantum dots (QDs) in the proximity of a metal nanoshell is investigated. Nanoshells can enhance the local density of states, leading to a strong-coupling regime where the excitation energy can coherently be transferred between the QDs and the nanoshell in the form of Rabi oscillations. The long-lived entangled states can be created deterministically by optimizing the shell thickness as well as the ratio of the distances between the QDs and the surface of the shell. The loss of the system is greatly reduced even when the QDs are ultraclose to the shell, which signifies a slow decay rate of the coherence information and longtime entanglement preservation. Our protocol allows for an on-demand, fast, and almost perfect entanglement even at strong carrier-phonon interaction where other systems fail.