Researchers from Singapore and China have used a superconducting quantum processor to study the phenomenon of quantum transport in unprecedented detail.
A better understanding of quantum transport, which can refer to the flow of particles, magnetisation, energy or information through a quantum channel, could propel advances in technologies such as nanoelectronics and thermal management.
"We're quite excited because this is, practically, a new paradigm of doing quantum transport experiments," says Centre for Quantum Technologies (CQT) Fellow Dario Poletti, whose co-corresponding authors for the new work published in Nature Communications on 22 November 2024 are Professor Haohua Wang from Zhejiang University (ZJU) and Professor Jie Hao from the Institute of Automation at the Chinese Academy of Sciences (CAS). He added, "We can now access information that we could not before with other previous implementations of quantum transport."
Dario, who is also an Associate Professor and Head of Cluster at Singapore University of Technology and Design (SUTD), and a researcher under the MajuLab International Research Laboratory, derived theoretical models of quantum transport with Dr Xiansong Xu and Dr Chu Guo, back when they were both PhD students in SUTD. Xiansong is now an Assistant Professor at Sichuan Normal University while Chu Guo is an Assistant Professor at Henan Key Laboratory of Quantum Information and Cryptography. They tested these models with experimentalists from ZJU and CAS.
Experiments performed on the ZJU team's 31-qubit quantum processor explored how a spin/particle current flows between two groups of qubits.
"The work also shows the usefulness of quantum simulation in the NISQ era," says Pengfei Zhang, a Postdoctoral Fellow at ZJU. Pengfei is the co-first author of the publication together with Yu Gao, a PhD student at ZJU, and Xiansong. NISQ refers to noisy intermediate-scale quantum devices.
A unified picture
Quantum transport happens when there is some imbalance or nonequilibrium between systems in contact. For example, a temperature difference results in heat flow until systems are thermalised, while voltage differences result in a current.
