Kato Group

Associate Professor

KATO,Takeo

Research Associate

SAKANO,Rui

The main research subject of our group is theory on quantum transport in nano-scale devices using various approaches. This research field is also called ‘mesoscopic physics', which has been studied for long time by focusing on quantum mechanical nature of electrons. Recently, mesoscopic physics based on new viewpoints is studied from such as nonequilibrium many-body phenomena, shot noise, high-speed drive phenomena, spintronics, and so on. We are constructing theories to explain these phenomena, by exploiting nonequilibrium statistical mechanics, fundamental theory of quantum mechanics, and many-body physics. Nonequilibruim transport properties of the Kondo quantum dots, electron and heat transport under time-dependent external fields, and many-body effect in thermal transport of phonons, can be cited as our recent research. We are also treating various research subjects related to many-body effects and nonequilibrium phenomena. Glass-like behavior in organic conductors and structural phase transition in solid oxygen can be cited as these activities. We are also collaborating with experimental groups in ISSP.

Upper panel: A schematic figure of the Hong-Ou-Mandel-type two-electron collision experiment. Two electrons injected from two quantum dots propagate along edge states, and collides at a central quantum point contact. Lower panel: The probability P , that two electrons scatter into the same edge states, is plotted as a function of a wavepacket delay time Δt.

The photon-assisted zero-bias noise (the solid line) and the equilibrium thermal noise (the dashed line) evaluated at the corresponding T _{eff} (the right inset) are displayed as a function of the strength of the external filed. The left inset: a schematic picture of the present model.

- Transport properties in mesoscopic systems
- Theory of quantum transport in interacting electron systems
- Fundamental theory of non-equilibrium statistical mechanics and quantum measurement

1.

PDF

Effect of Interaction on Reservoir-Parameter-Driven Adiabatic Charge Pumping via a Single-Level Quantum Dot System: M. Hasegawa and T. Kato, J. Phys. Soc. Jpn. **87** (2018) 044709.

2.

PDF

Current cross-correlation in the Anderson impurity model with exchange interaction: R. Sakano, A. Oguri, Y. Nishikawa and E. Abe, Phys. Rev. B **97** (2018) 045127 (1-13).

3.

PDF

Spin Current Noise of the Spin Seebeck Effect and Spin Pumping: M. Matsuo, Y. Ohnuma, T. Kato and S. Maekawa, Phys. Rev. Lett. **120** (2018) 235120 (1-5).

4.

「1 次元相互作用電子系中のポテンシャル散乱問題に関する数値的研究」 島田 典明, 東京大学理学系研究科 (2018).

5.

PDF

Temperature-Driven and Electrochemical-Potential-Driven Adiabatic Pumping via a Quantum Dot: M. Hasegawa and T. Kato, J. Phys. Soc. Jpn. **86** (2017) 024710 (1-13).