Characteristics of small devices having sizes of the de Broglie wavelength (～0.1μm) can directly reflect the features of fundamental quanta such as electrons, spins and photons. Precise control over the quantum properties can give rise to innovation in information security and information technology.
This project aimed to make artificial atoms (quantum dots) using semiconductors, and then to explore quantum physics and to build up new concepts of quantum information technology. The project developed two quantum dots having micrometer-sized magnet and succeeded nondestructive readout of electron spins from the quantum dots by controlling them individually. The project also created three quantum dots necessary for quantum error correction, explored the physical phenomenon, and acquired principles for quantum gate configuration to implement multiple quantum bits. In addition, the project gained many toeholds in quantum information technology such as quantum information transfer, detection and control of nuclear spins, and so on.
This research project was jointly carried out with the Delft University of Technology in Netherlands and the University of Basel in Switzerland. The Japanese research group studied the fundamental physical properties of the quantum-dot-spins and quantum information processing. The Dutch research group worked on coherence-breaking in quantum dots for implementing quantum information processing and quantum physics in novel quantum substances such as carbon nanotubes. The Swiss research group developed new theories for supporting quantum information technology such as a theoretical proposal to experiments. These achievements from this research project are expected to apply to quantum computers and quantum communication in the future.