Quantum computing is a new paradigm of computation based of fundamental principles of quantum mechanics. The weird properties of quantum mechanics, which are very counterintuitive for us, such as quantum superposition and quantum entanglement, play key roles in quantum information processing. Quantum computers, once realized, is expected to largely outperform conventional computers for particular types of computational tasks such as simulations of energy levels and dynamics of molecules and strongly correlated materials. Applications of quantum computing in other problems such as machine learning are currently investigated.
Superconducting electric circuits can process quantum information. An elementary unit of quantum information, a quantum bit, or qubit in short, is represented by a physical system with two distinct energy levels. In superconducting circuits, qubits are realized as quantized energy levels of a collective excitation mode of electrons. Thanks to the superconductivity, the energy loss is minimal, which makes the qubit coherent.
We are developing superconducting quantum circuits for quantum information processing as well as quantum communication and sensing.

Circuit Chips with Integrated Superconducting Qubits
Production: Professor Yasunobu Nakamura
Size: 1290×1290×330
Collection: Department of Applied Physics, School of Engineering, The University of Tokyo
Research Center for Advanced Science and Technology, The University of Tokyo
Prototype of integrated superconducting quantum-bit circuits developed for quantum computing.
Each chip (1x1cm) in the silicon wafer contains an array of 16 quantum bits.