The 1920's saw the development of quantum theory to explain distinctly non- classical (non-Newtonian) physical phenomena. Since then, experimental breakthroughs have greatly increased our control over microscopic systems. Not only has this led to increasingly precise confirmation of quantum physics as our best description of the world at small energy scales, it has also revealed potential practical advantages in the emerging field of quantum technology.
Quantum technologies aim to exploit the laws of quantum physics to engineer improvements beyond what is possible within a classical framework. The most well- known example of a proposed quantum technology the quantum computer, and though many challenges remain before quantum computers reach their full potential, there has been much progress in their development. Other examples are quantum metrology (which aims to exploit quantum principles to significantly improve the precision of measurements) and quantum communication (which promises to protect the privacy of your communication through secure key distribution).
A large-scale quantum computer would be able to perform some computational tasks (for example integer factorization, database search, or the simulation of quantum many-body systems) much more efficiently than a classical computer. Interaction of a quantum computer with its environment introduces noise that destroys its computational advantage, but theory has shown that this obstacle can be overcome with various anti-noise techniques. We are interested in exploring the limits of quantum information processing as well as the hurdles to building a quantum computer in the lab. Areas of current research include error correcting codes, simulation of remote interactions, implementing algorithms via quantum walks, and visualizing quantum information processing with pseudo-probability distributions.
Quantum repeaters are a necessary component of quantum computation and quantum communication between widely separated devices. Over the past fifteen years, ideas and technology in the field of quantum repeaters have come a long way from their idealized conceptual infancy and are fast approaching the point of feasibility. Here at the Global Research Centre for Quantum Information Science, we take a particular interest in bringing into the foreground practical details at the heart of proposals for repeater technology. Considering those practical constraints involved in implementing promising theoretical schemes with real-world quantum systems, we work to identify a path toward high-fidelity, scalable quantum repeaters.
No single physical platform has yet emerged as a a clear favourite for the general implementation of quantum technologies. Established candidate systems include trapped ions and atoms, photonic circuits, doped and structured semiconductors and superconducting circuits, but a host of alternative proposals at varying levels of maturity also remain to be investigated, as well as hybrid combinations. Here at the Global Research Center for Quantum Information Science we have worked with a particular focus on defect centers in diamond, especially the nitrogen-vacancy center. We retain, however, a strong interest in the comparative strengths and weaknesses of different systems as they relate to different applications.
The precise measurement of physical parameters is a crucial task in many branches of science. Since the 1980's, theory has shown that some quantum resources - such as entanglement - can be exploited to drastically improve the precision of some measurements. However, decoherence makes it difficult to achieve a quantum advantage with current technology. In the Quantum Information Science Theory Group we are interested in this, and other hurdles to implementing ultra-precise quantum measurement schemes in experiment, as well as the development of new robust quantum measurement schemes.