Researchers from the University of Sussex and Universal Quantum have shown for the first time that quantum bits (qubits) can be transferred directly across quantum computer microchips with record-breaking speed and accuracy. This solution solves a significant hurdle in the development of quantum computers large and robust enough to tackle complicated problems of crucial societal concern.
“As quantum computers grow, we will eventually be constrained by the size of the microchip, which limits the number of quantum bits such a chip can accommodate. As such, we knew a modular approach was key to make quantum computers powerful enough to solve step-changing industry problems. In demonstrating that we can connect two quantum computing chips — a bit like a jigsaw puzzle — and, crucially, that it works so well, we unlock the potential to scale-up by connecting hundreds or even thousands of quantum computing microchips.”
Professor Winfried Hensinger, Professor of Quantum Technologies at the University of Sussex and Chief Scientist and Co-founder at Universal Quantum
The researchers, led by Dr. Mariam Akhtar, Research Fellow at the University of Sussex and Quantum Advisor at Universal Quantum, together with Ph.D. student Falk Bonus and Postdoctoral Fellow Foni Raphael Le Brun-Ricalens has demonstrated a quantum matter link in which ion qubits are transmitted between adjacent QC modules in the paper.
Platforms based on trapped atomic ions provide an excellent foundation for developing QCs and quantum simulators. When compared to alternative physical implementations, encoding qubits in the internal electronic states of trapped ions provides the highest quantum gate fidelities and the longest coherence periods.
Understanding the quantum matter link
The scientists demonstrate how they used a new and powerful technique, dubbed ‘UQConnect,’ to use electric field links to enable qubits to move from one quantum computing microchip module to another with unprecedented speed and precision in the research paper, published last 8 February 2023 in Nature Communications. This enables chips to be slotted together like jigsaw puzzle pieces to create a more powerful quantum computer.
“Our relentless focus is on providing people with a tool that will enable them to revolutionise their field of work. The Universal Quantum and University of Sussex teams have done something truly incredible here that will help make our vision a reality. These exciting results show the remarkable potential of Universal Quantum’s quantum computers to become powerful enough to unlock the many life-changing applications of quantum computing.”
Dr Sebastian Weidt, CEO and Co-founder of Universal Quantum, and Senior Lecturer in Quantum Technologies at the University of Sussex
Furthermore, they demonstrated that the link has no discernible effect on the qubit’s phase coherence. The quantum matter link provides a feasible way to connect quantum charge-coupled devices (QCCD). Their research will aid in developing modular QCs capable of fault-tolerant utility-scale quantum computation.
The University of Sussex and Universal Quantum team transported the qubits with a success rate of 99.999993% and a connection rate of 2424/s, both of which are world records and orders of magnitude better than previous solutions.
“The DLR contract was likely one of the largest government quantum computing contracts ever handed out to a single company. This is a huge validation of our technology. Universal Quantum is now working hard to deploy this technology in our upcoming commercial machines.”
Dr Sebastian Weidt, CEO and Co-founder of Universal Quantum, and Senior Lecturer in Quantum Technologies at the University of Sussex
The scientists also confirmed that the ‘strange’ quantum character of the qubit remained unaltered during transit. For example, while linking the modules at world-record speed, the qubit can be both 0 and 1 simultaneously.
Universal Quantum has received a €67 million contract from the German Aerospace Center (DLR) to create two quantum computers that will use this technology. The University of Sussex spin-off was also designated a 2022 Institute of Physics award winner in the Business Start-up category.
“The team has demonstrated fast and coherent ion transfer using quantum matter links. This experiment validates the unique architecture that Universal Quantum has been developing — providing an exciting route toward truly large-scale quantum computing.”
Dr. Mariam Akhtar, Research Fellow at the University of Sussex and Quantum Advisor at Universal Quantum,
“It’s fantastic to see that the inspired work of the University of Sussex and Universal Quantum physicists has resulted in this phenomenal breakthrough, taking us a significant step closer to a quantum computer that will be of real societal use. These computers are set to have boundless applications — from improving the development of medicines, creating new materials, to maybe even unlocking solutions to the climate crisis. The University of Sussex is investing significantly in quantum computing to support our bold ambition to host the world’s most powerful quantum computers and create change that has the potential to positively impact so many people across the world. And with teams spanning the spectrum of quantum computing and technology research, the University of Sussex has both a breadth and a depth of expertise in this. We are still growing our research and teaching in this area, with plans for new teaching programmes, and new appointments.”
Professor Sasha Roseneil, Vice-Chancellor of the University of Sussex
“This is a very exciting finding from our University of Sussex physicists and Universal Quantum. It proves the value and dynamism of this University of Sussex spin-out company, whose work is grounded in rigorous and world-leading academic research. Quantum computers will be pivotal in helping to solve some of the most pressing global issues. We’re delighted that Sussex academics are delivering research that offers hope in realising the positive potential of next-generation quantum technology in crucial areas such as sustainability, drug development, and cybersecurity.”
Professor Keith Jones, Interim Provost and Pro-Vice Chancellor for Research and Enterprise at the University of Sussex
Read the study here.