A joint research group led by Professor Kazuhiko Hirakawa (Institute of Industrial Science), Project Research Associate Shaoqing Du, Professor Yasujiro Murata and his colleagues at Kyoto University, and Professor Yoshiro Hirayama and his colleagues at Tohoku University has measured the tunneling current in an ultra-fine transistor structure in which a single water molecule is trapped inside a fullerene molecule. This is the first time that they have succeeded in detecting the quantum mechanical rotational motion of water molecules inside a fullerene molecule. This achievement is a basic technology for reading the quantum information of a single molecule or a single atom, and is expected to lead to quantum information processing in which the quantum state of a single atom is the basis of information in the future. The paper was published in the online edition of Nano Letters on January 2.