Charge-noise-insensitive gate operations for always-on, exchange-only qubits

TL;DR

This paper presents a novel exchange-only qubit design that remains insensitive to charge noise at a sweet spot, enabling robust single- and two-qubit gates solely via exchange pulses, and demonstrates interconversion with other three-spin qubits.

Contribution

It introduces an always-on, charge-noise-insensitive qubit with exchange-only control and shows how to convert it to other three-spin qubits for quantum computing.

Findings

Qubit operates at a true sweet spot against charge noise.

Single- and two-qubit gates achieved using exchange pulses.

Interconversion with other three-spin qubits demonstrated.

Abstract

We introduce an always-on, exchange-only qubit made up of three localized semiconductor spins that offers a true "sweet spot" to fluctuations of the quantum dot energy levels. Both single- and two-qubit gate operations can be performed using only exchange pulses while maintaining this sweet spot. We show how to interconvert this qubit to other three-spin encoded qubits as a new resource for quantum computation and communication.