Coherent control of three-spin states in a triple quantum dot

TL;DR

This paper demonstrates for the first time the coherent control of three-spin states in a triple quantum dot, enabling advanced quantum information processing functionalities such as error correction and protected qubit encoding.

Contribution

It introduces a novel method for coherent manipulation of three-spin states using the Landau-Zener-Stückelberg approach in triple quantum dots.

Findings

Successful coherent control of three-spin states achieved

Maintained coherence while varying exchange couplings

Demonstrated pairwise exchange control in triple quantum dots

Abstract

Spin qubits involving individual spins in single quantum dots or coupled spins in double quantum dots have emerged as potential building blocks for quantum information processing applications. It has been suggested that triple quantum dots may provide additional tools and functionalities. These include the encoding of information to either obtain protection from decoherence or to permit all-electrical operation, efficient spin busing across a quantum circuit, and to enable quantum error correction utilizing the three-spin Greenberger-Horn-Zeilinger quantum state. Towards these goals we demonstrate for the first time coherent manipulation between two interacting three-spin states. We employ the Landau-Zener-St\"uckelberg approach for creating and manipulating coherent superpositions of quantum states. We confirm that we are able to maintain coherence when decreasing the exchange coupling of one spin with another while simultaneously increasing its coupling with the third. Such control of pairwise exchange is a requirement of most spin qubit architectures but has not been previously demonstrated.