Superconducting nanodevices: fundamental investigations and application to quantum information and sensitive detection

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Quantum mechanics is the fundamental theory of nature. The quantum description of the physical world is often in marked contrast with our intuition. For instance, any attempt to observe a quantum object changes its state in a random and irreversible manner. In recent decades, advances in science and technology made it possible to isolate and manipulate simple quantum systems. Having a good handle on quantum systems gives new opportunities to understand the foundations of quantum mechanics. Moreover, recent research revealed that when information is encoded using quantum systems new opportunities for applications arise. Quantum computers outperform classical computers in many relevant tasks. In addition, quantum systems provide a way to transmit information in a secure manner. Both fundamental research and prospective applications using quantum systems focused traditionally on atoms and photons, which are weakly coupled to the surrounding world, making quantum effects prominent. However, in recent years genuine quantum effects were observed in solid-state systems, where the quantum behavior can be engineered. Superconducting quantum circuits, which are devices based on superconductors, are one of the most promising types of systems for research on foundations and applications of quantum mechanics. Our research on superconducting quantum circuits addresses fundamental aspects of their physics and two types of practical applications. We will explore the physical origin of the magnetic flux fluctuations observed in superconducting devices. This type of fluctuation has many puzzling features and is detrimental to applications. Understanding the origin of flux noise is one of the most important problems in the field of condensed matter physics. We will use a set of tools recently developed in our group for systematic experimental investigations of flux noise. The first practical application we will explore is quantum computing using superconducting circuits. We will investigate both the implementation of logic gates and the protection against unavoidable errors in a quantum computer. The second application that we will pursue is the development of ultra-sensitive magnetic field sensors. We will further develop a new type of magnetometer invented by our group and we will apply it to measurements of small magnetic fields generated by the mechanical vibrations of nanometer size resonators and by small magnetic molecules. This research will be carried out by undergraduate and graduate students, and by postdoctoral researchers. This proposal requires funding for the salaries of these researchers and for operation and equipment costs. Our research will have a major impact for fundamental research in quantum mechanics and quantum technologies. It will contribute to further establishing Canada as one of the leading countries in quantum information and technologies. Canada will also benefit through the training of the individuals working on this project, who will acquire skills transferable to many fields of research and industry.