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[Keio Spintronics Network - Tarucha-Oiwa Laboratory , University of Tokyo] Tokyo University's Tarucha-Oiwa Laboratory is doing experimental research on physics and hardware for quantum information processing, which utilizes electron transport, spin correlation, and spin in low-dimensional electron systems. The laboratory is looking at electron systems in one and zero dimensions, which can be achieved through semiconductor microfabrication. The researchers study the fundamental physics of many-body effects in artificial atoms and molecules, spin phenomena in strong magnetic fields, the effects of conduction phenomena on electron and nuclear spin, electronic properties in one-dimensional Tomonaga-Luttinger liquids, and spin quantum computing. In addition, the Lab is developing a method of observing state density directly, using a surface-sensitive scanning probe. "In our Lab, the main theme is how to precisely control, investigate, and utilize the quantum mechanical properties of the most basic particles in semiconductors -- the atoms. We started this research about 15 years ago. At that time, when we fabricated small structures called quantum dots, we were the first in the world to find out experimentally how to confine electrons in quantum dots, investigate their properties, and control their states." When electrons are injected one by one into artificial atoms, they occupy orbits, due to the quantum confinement effect, and take on energy levels, like those in real atoms. Making artificial atoms requires extremely precise control, and worldwide, the first person to achieve this was Professor Tarucha. "The behavior of single electrons has actually become visible. So during the last decade, we've been researching whether we can utilize this to understand more phenomena, or apply it to new technologies. What's emerged from this research is that the quantum mechanical nature of electron spin can be used to construct quantum information, and when this quantum information is used in computing, it's possible to create a quantum computer. We're attempting to build a quantum computer, using electron spin as the basic unit." Quantum computing uses quantum bits, which can have states that are both zero and one, through quantum mechanical superposition. If there are n quantum bits, then 2 to the power n states can be computed simultaneously. In theory, this would enable computers to do, in just a few hours, calculations that today's fastest supercomputer can't do even in several thousand years. "To make that much progress would require ten thousand or a hundred thousand bits. But we can't make ten thousand bits right away. We need a procedure for skillfully increasing the number of bits from the current level. What researchers worldwide, including our group, are doing requires only one or two bits, and in a few years, we'll probably be able to use five or ten bits. It's predicted that the number of bits will double every 18 months to 2 years. If that's so, then 20 or 30 years from now, I think it might be possible to achieve 10,000 bits or 100,000 bits. You might ask if the benefits won't be visible for 20 or 30 years. Well, to make progress, we need to get through the era of using 10 bits or 100 bits, which could be possible in 5 or 10 years. At that stage, I think a variety of results will emerge from this research."