Periodic Reporting for period 2 - QUIST (Quantum information transfer between hole spins and topological states) Reporting period: 2021-05-01 to 2022-10-31 Summary of the context and overall objectives of the project Large-scale quantum computers have the potential to address large societal challenges. Semiconductor quantum dots define a compelling starting point for building such computers. However, it is currently unclear how to scale quantum dots to large numbers. One vision is based on networked computing, where local registers of qubits are interconnected using long-rang quantum links. This proposal aims to build such local registers, realize long-range quantum links, and integrate them together as a step toward scalable quantum technology. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far We have demonstrated that germanium quantum dot qubits can be operated with extremely high fidelity, reaching fidelities of 99.99%. In addition, we have demonstrated that germanium quantum dot qubits can be grouped together to program rudimentary error correction circuits. This work simultaneously demonstrates that quantum information can be transferred from one qubit to another qubit. Finally, we have demonstrated that superconductivity can be induced in germanium quantum well, marking an important step toward superconductor-semiconductor hybrids for coherent quantum links. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) The realization of single qubit performance with fidelities of 99.99% marks the state-of-the-art for semiconductor quantum dots and constitutes a quality that is several times better than any previous work. Simultaneously, the demonstration of rudimentary error correction is an important step toward testing, designing, and operating quantum algorithms using semiconductor technology.
