Dynamic generation of GHZ states with coupled charge qubits

TL;DR

This paper demonstrates a proof-of-principle method for dynamically generating GHZ entangled states using coupled charge qubits in quantum dots, analyzing the conditions, dynamics, and decoherence effects involved.

Contribution

It introduces a novel approach to generate GHZ states in charge qubits with detailed analysis of the dynamics and decoherence effects.

Findings

Successful numerical modeling of GHZ state formation in quantum dot systems

Identification of key tunneling processes responsible for entanglement

Quantification of charge dephasing impact on state generation

Abstract

In this paper, we present a proof-of-principle of the formation of pure maximally entangled states from the Greenberger-Horne-Zeilinger class, in the experimental context of charged quantum dots. Each qubit must be identified as a pair of quantum dots, sharing an excess electron, coupled by tunneling. The electron-electron interaction is accounted for and is responsible for the coupling between the qubits. The interplay between coherent tunneling events and many-body interaction gives rise to the formation of highly entangled states. We begin by treating the problem of encoding three-qubits in a system with three pairs of quantum dots, and the numerical analysis of the exact quantum dynamics to find the conditions for the generation of the GHZ states. An effective two-level model sheds light on the role of a high-order tunneling process behind the dynamics. The action of the main decoherence process, the charge dephasing, is quantified in the process. We then evaluate the physical requirements for the dynamical generation of GHZ states in a $N$ qubit scenario, and its challenges.