A logical qubit in a linear array of semiconductor quantum dots

TL;DR

This paper proposes a scalable logical qubit architecture using a linear array of semiconductor quantum dots, employing global control and local exchange interactions, with adapted error correction protocols and near-term validation plans.

Contribution

It introduces a practical scheme for logical qubits in a one-dimensional quantum dot array with tailored control and error correction, suitable for near-term experiments.

Findings

Estimated error correction threshold of 1e-4.

Designed control scheme using broadband microwave pulses.

Outlined experimental validation sequence for four coupled dots.

Abstract

We design and analyze a logical qubit composed of a linear array of electron spins in semiconductor quantum dots. To avoid the difficulty of fully controlling a two-dimensional array of dots, we adapt spin control and error correction to a one-dimensional line of silicon quantum dots. Control speed and efficiency are maintained via a scheme in which electron spin states are controlled globally using broadband microwave pulses for magnetic resonance while two-qubit gates are provided by local electrical control of the exchange interaction between neighboring dots. Error correction with two-, three-, and four-qubit codes is adapted to a linear chain of qubits with nearest-neighbor gates. We estimate an error correction threshold of 1e-4. Furthermore, we describe a sequence of experiments to validate the methods on near-term devices starting from four coupled dots.