Researchers have developed a technique for analysing large superconducting circuits, which could facilitate advancements in the field of quantum computing.
The next revolution in computing and information processing lies in the domain of quantum mechanics. In the future, quantum computers are projected to solve incredibly complex problems far beyond the capability of current supercomputers.
In order to advance quantum computers to their full potential, innovative new tools and techniques must be developed. To assist in this process, researchers at Northwestern University have developed and tested a theoretical tool for analysing superconducting circuits, which employ the smallest units of quantum computers – superconducting quantum bits, or qubits – to store information.
The researchers’ findings have been published in the journal Physical Review Research.
Modelling superconducting circuit size
The size of circuits is significant because protection from detrimental noise has a tendency to come at the cost of enhanced circuit complexity. Currently, there are very few tools that take on the challenge of modelling large circuits, thus meaning the Northwestern approach is an essential contribution to the research community.
“Our framework is inspired by methods originally developed for the study of electrons in crystals and allows us to obtain quantitative predictions for circuits that were previously hard or impossible to access,” explained Daniel Weiss, corresponding and first author of the paper.
Department of Energy
Koch is an associate professor of physics and astronomy in Weinberg College of Arts and Sciences, as well as a member of the Superconducting Quantum Materials and Systems Center (SQMS) and the Co-design Center for Quantum Advantage (C2QA).
Both national centres were founded last year by the US Department of Energy (DOE). SQMS is centred on developing and deploying a beyond-state-of-the-art quantum computer based on superconducting technologies. C2QA is constructing the necessary tools for developing scalable, distributed and fault-tolerant quantum computer systems.
“We are excited to contribute to the missions pursued by these two DOE centres and to add to Northwestern’s visibility in the field of quantum information science,” Koch added.
Extracting qualitative information
In their study, the team demonstrated the efficacy of their tool by extracting qualitative information that was previously unattainable from a protected circuit.
The group specifically researched and analysed protected qubits. These qubits are protected from detrimental noise by design and could potentially produce coherence times (how long quantum information is retained) that are far longer than current state-of-the-art qubits.
These superconducting circuits are unavoidably massive, and the novel tool is a means for quantifying the behaviour of these circuits. Before the development of the new tool, there were some tools capable of analysing large superconducting circuits, but each only works properly when certain conditions are met. Meanwhile, the Northwestern technique is complimentary and works well when these other tools may give suboptimal results.