In our new, state-of-the-art Millikelvin Quantum Science lab facility, QSI's experimental and theory teams are working closely together to explore both fundamental quantum theory and key techniques in quantum computing and quantum information processing.
Technology is one of the primary driving forces behind the rapidly developing field of quantum information science. With an ever-increasing number of new start-ups emerging and major investment by big-tech giants like Google, IBM, Intel and Microsoft, massive technology translation and commercialisation efforts are taking place world-wide in areas like quantum computing and quantum key distribution. Critical to the realisation of practical “at scale” quantum technologies that can outperform traditional technologies are both advanced core theoretical concepts and modelling, as well as state-of-the-art hardware fabrication and experimental control techniques. In the quantum experiments and hardware research program, our QSI theory team has collaborated closely with world-leading experimental groups to make many key contributions to both designing and modelling next-generation experiments. And in our state-of-the-art Millikelvin Quantum Science lab facility, our new QSI experimental team is working closely with our theory team to explore both fundamental quantum theory and key techniques in quantum computing and quantum information processing.
Program Leader: A/Prof Nathan Langford
Circuit quantum electrodynamics (circuit QED) is one of the leading platforms for scaleable quantum computing, and the focus of massive industry research efforts at Google, IBM and Intel, as well as leading quantum start-ups like Rigetti. Exploiting the power and flexibility of circuit QED, the QSI experimental team is developing innovative quantum devices to investigate both fundamental quantum theory and practical quantum information processing techniques.
In the early 1980s, Richard Feynman predicted that one of the most important applications of quantum mechanical computing devices would be as a tool to simulate and model the behaviour of other quantum systems of interest. Such quantum simulations are still likely to be the first important applications of near-term quantum computers, harnessing a key advantage of quantum machines over classical ones. Our research aims to build circuit QED based quantum simulators and study the challenges associated with realising large-scale simulations with such devices.
Many of the most promising quantum technologies, like quantum networks and quantum key distribution, build intimately on the most fundamental principles of quantum theory. And these principles often also lie at the heart of the most pressing roadblocks to practical quantum technologies. This research aims to investigate the fundamental quantum characteristics that limit important techniques in practical quantum information processing, like characterisation, quantum control and digitisation.
Theory of quantum experiments
The biggest challenges to realising practical quantum technologies arise when trying to increase the system sizes to scales where quantum advantages surpass existing classical technologies, especially in relation to the exquisite fragility of quantum behaviour and coherence. As well as placing stringent constraints on hardware, reaching such system sizes requires the most advanced algorithms, error correction and control protocols, and detailed descriptions of system imperfections. This theoretical research aims to minimise hardware overheads by optimising algorithms and system control at all layers of the quantum “stack”. The QSI theory team also works closely with leading experimental collaborators to characterise and benchmark the performance of state-of-the-art quantum information processing platforms.
- Akram Youssry*, Robert J. Chapman, Alberto Peruzzo, Christopher Ferrie, Marco Tomamichel. Modeling and Control of a Reconfigurable Photonic Circuit using Deep Learning. arXiv:1907.08023 (2019).
- Juan Pablo Dehollain, Uditendu Mukhopadhyay, Vincent P. Michal, Yao Wang, Bernhard Wunsch, Christian Reichl, Werner Wegscheider, Mark S. Rudner, Eugene Demler, and Lieven M.K. Vandersypen. Nagaoka ferromagnetism observed in a quantum dot plaquette. arXiv:1904.05680 (2019).
- He-Liang Huang, Xi-Lin Wang, Peter P. Rohde, Yi-Han Luo, You-Wei Zhao, Chang Liu, Li Li, Nai-Le Liu, Chao-Yang Lu, Jian-Wei Pan. Demonstration of topological data analysis on a quantum processor. Optica (2018).
- N. K. Langford, R. Sagastizabal, M. Kounalakis, A. Bruno, C. Dickel, F. Luthi, D. J. Thoen, A. Endo, and L. DiCarlo. Experimentally simulating the dynamics of quantum light and matter at deep-strong coupling. Nat. Commun. (2017).
- Markus Jerger, Yarema Reshitnyk, Markus Oppliger, Anton Potočnik, Mintu Mondal, Andreas Wallraff, Kenneth Goodenough, Stephanie Wehner, Kristinn Juliusson, Nathan K. Langford, and Arkady Fedorov. Contextuality without nonlocality in a superconducting quantum system. Nat. Commun. (2016).
- Nathan K. Langford, Sven Ramelow, Robert Prevedel, William J. Munro, Gerard J. Milburn, Anton Zeilinger. Efficient quantum computing using coherent photon conversion. Nature (2011).