Researchers map electrons to move one step closer to better quantum computers

Australian researchers have determined the ‘sweet spot’ for positioning qubits to achieve high-accuracy quantum computers.

The research, published today in Nature Communications, showed precision placement has proven to be essential for developing robust interactions – or coupling – between qubits.

The study was conducted through collaborated research between the University of Melbourne and UNSW Sydney.

Quantum electronics researcher and co-author, University of Melbourne’s Dr Muhammad Usman, said qubits are the fundamental building blocks of a large-scale quantum computer.

“Understanding the interactions between qubits is the key to building high fidelity quantum logic gates, thereby reducing errors in the quantum computer, but due to the atomic distances involved this has been impossible until now,” Dr Usman said.

Centre for Quantum Computation and Communication Technology Deputy Director and research co-author, University of Melbourne’s Professor Lloyd Hollenberg, said quantum computing is an emerging paradigm with potential to offer tremendous computing power in the future.

“Researchers from UNSW Sydney were able to obtain atomic-resolution images of coupled electron wave functions, while we conducted advanced theoretical simulations to analyse these images which was crucial to map two-qubit interactions for the future of quantum computers,” Professor Hollenberg said.

Lead researcher from UNSW Sydney, Professor Sven Rogge, said: “For almost two decades, researchers have struggled to pinpoint the nature electron interactions which been an obstacle for scaling-up quantum computers. We have now located the optimal position to create reproducible, strong and fast interactions between the qubits,”

“We need these robust interactions to engineer a multi-qubit processor and, ultimately, a useful quantum computer.”

Researchers from the University of Melbourne, UNSW Sydney and Purdue University in the United States are part of world-leading research efforts at the ARC Centre for Quantum Computation and Communication Technology, focussing on research and technology development for large-scale quantum computing.