Quantum Entanglement of Excitons in Coupled Quantum Dots

TL;DR

This paper explores how to generate and control entangled exciton states in coupled quantum dots using optical methods, demonstrating robust creation of Bell and GHZ states with potential for quantum information applications.

Contribution

It introduces new methods for producing GHZ states in three quantum dots with shorter generation times, expanding on previous configurations.

Findings

Bell and GHZ states can be robustly generated at avoided crossings.

Population transfer analyzed via dressed-state picture.

GHZ states achievable in a three-dot system with shorter times.

Abstract

Optically-controlled exciton dynamics in coupled quantum dots is studied. We show that the maximally entangled Bell states and Greenberger-Horne-Zeilinger (GHZ) states can be robustly generated by manipulating the system parameters to be at the avoided crossings in the eigenenergy spectrum. The analysis of population transfer is systematically carried out using a dressed-state picture. In addition to the quantum dot configuration that have been discussed by Quiroga and Johnson [Phys. Rev. Lett. \QTR{bf}{83}, 2270 (1999)], we show that the GHZ states also may be produced in a ray of three quantum dots with a shorter generation time.