Quantum Condensed Phases Research Team

Principal Investigator

PI Name Kimitoshi Kono
Degree D.Sci.
Title Team Leader
Brief Resume
1982Ph.D., University of Tokyo
1982Research Associate, Hyogo University of Teacher Education
1987Associate Professor, Hyogo University of Teacher Education
1989Associate Professor, Institute of Physics, University of Tsukuba
1992Associate Professor, Institute for Solid State Physics, University of Tokyo
2000Chief Scientist, Low Temperature Physics Laboratory, RIKEN
2013Team Leader, Quantum Condensed Phases Research Team, Quantum Information Electronics Division, RIKEN Center for Emergent Matter Science (-present)
2018Professor, Department of Electrophysics, National Chiao Tung University (-present)


We will develop techniques to manipulate single electrons and ions trapped at an extremely clean surface of liquid helium, which will be utilized to fabricate quantum effect devices. This includes lateral confinement techniques and control of quantum transitions between discrete energy levels due to the abovementioned confinement and due to surface states, and atoms and ions imbedded in liquid helium.

Research Fields

Low Temperature Physics


Superfluidity, Surface Phenomena
Two-dimensional electron system
Quantum computing


Study of elementary excitation of superfluid helium with Dy atoms imbedded in liquid helium

Interaction between helium (He) atoms and metallic atoms and ions imbedded in liquid He results in various intriguing phenomena.  Laser spectroscopy of Dysprosium (Dy) atoms introduced in liquid He by laser ablation has been successfully carried out to elucidate the creation of a single elementary excitation of superfluid He, phonon and roton, for the first time.

 Absorption spectra of Dy atoms revealed a clear signature of a sharp zero-phonon line (ZPL) and broad phonon-wing (PW) which is associated with the creation of a single elementary excitation of superfluid helium.  The gap between the ZPL and PW is indication of a peculiar dispersion relation of the elementary excitation of superfluid He.

 This investigation answered the long standing question why this spectrum structure has not been found, so far.  It is because the former investigation may have been carried out under strong light intensity, and hence, absorption saturation has been occurred.



Kimitoshi Kono

Team Leader kkono[at]riken.jp R