84th CEMS Colloquium


Prof. Kensuke Kobayashi (The University of Tokyo)


17:30 - 18:30, September 23, 2020 (Wednesday)


Okochi-Hall, RIKEN


Strongly Correlated Quantum Liquids Probed by Non equilibrium Fluctuations


Nanotechnology has enabled us to study mesoscopic systems, namely, electronic devices that work in quantum regime. They have been serving as ideal test bed to demonstrate various quantum effects in a controllable and thus transparent way, because electron transport through
a single quantum site can be precisely measured. These days, current fluctuations in such systems are invoking great interest [1].

In this talk, I would like to discuss what we can learn from mesoscopic fluctuations. After introducing the basic of mesoscopic transport, I will talk about the fluctuations of the many body state formed at a quantum dot in the Kondo regime [2-4]. Such many body state is exactly the realization of strongly correlated quantum liquids described by Landau’s Fermi liquid theory. By using a carbon nanotube quantum dot, we demonstrate a precise experimental test of the Fermi liquid theory extended to the non equilibrium [5-7]. Our achievement will open a new way to explore quantum many body physics through fluctuations, which stands on firm ground even out of equilibrium beyond the conventional theory.

[1] K. Kobayashi, Proceedings of the Japan Academy, Ser. B 92, 204 (2016).
[2] M. Ferrier et al., Nature Phys. 12, 230 (2016).
[3] M. Ferrier, et al., Phys. Rev. Lett. 118, 196803 (2017).
[4] T. Hata, et al., Phys. Rev. Lett. 121, 247703 (2018).
[5] E. Sela, Y. Oreg, F. von Oppen, and J. Koch, Phys. Rev. Lett. 97, 086601 (2006).
[6] C. Mora, Phys. Rev. B 80, 125304 (2009).
[7] R. Sakano, T. Fujii, and A. Oguri, Phys. Rev. B. 83, 075440 (2011).