Research Themes

We are doing theoretical study of material science.
Main interest is to clarify the mechanism of physical phenomena in the systems where quantum fluctuation and electron correlation play essential role. By clarifying theoretically unresolved phenomena beyond conventional understanding, we reveal universal concept underlying each material. The ultimate goal of research is to create qualitatively new concept. To get qualitatively new results, it is often necessary to develop new theoretical framework itself. So, we are also trying to develop new theoretical method such as analytic theory, numerical algorithm and computational technique. We are also interested in proposing new physical phenomena theoretically and making theoretical material design.

• Magnetism and topology in Tb-based icosahedral quasicrystal and approximant
  
• Development of the formulation of the crystalline-electric-field theory in quasicrystal
  
• New quantum critical phenomena in itinerant electron systems with strong local correlations
   ⇒ Development of new framework of the mode-coupling theory of critical Yb (Ce)-valence fluctuations
   ⇒ Material exploration of new quantum critical phenomena
• Mechanism of emergence of T/B scaling in β-YbAlB₄
  
• Robust quantum criticality in heavy-electron systems on quasicrystal
  
• Magnetic-field control of valence transition in Ce- and Yb-based heavy electron systems
  
• Superconductivity emerging near quantum critical point of valence transition
  
• Quantum spin liquid on frustrated two-deimensional systems
  
• Importance of density fluctuations in 4/7 registered solid phase of ³He on graphite
  
• Development of grand-canonical path-integral renormalization group method
   ⇒ Development of new numerical algorithm without negative sign problem beyond quantum Monte Carlo method
• Unified understanding of filling- and band-width-control Mott transitions
  
• Unified explanation for anomalies in ferromagnetic superconductor UGe₂