[Icqm_seminar] 5.28 weekly seminar

报告题目： Fluctuation theorem in quantum conductors 报告人： Yasuhiro Utsumi 报告时间： 2014.5.28（周三）下午4:00 报告地点：理科5号楼607 联系人： Ryuichi shindou Abstract: Recently the exchange fluctuation theorem for the electric current has been demonstrated experimentally in the milli-Kelvin regime by using semiconductor nano-devices, single-electron transistors [1] and an Aharonov-Bohm interferometer [2]. At low temperatures, it turned out that the environmental effect and/or the measurement back action effect cannot be neglected. In the first part of my talk, I will review experiments on the fluctuation theorem of the single-electron transport through a double quantum dot [1]. Then I will discuss the back action effect from the quantum-point contact electrometer [3] and the finite bandwidth effects of the detector [4]. They both effectively enhance the temperature. In the second part, I will explain an experimental demonstration of the quantum fluctuation theorem using the Aharonov-Bohm interferometer [2]. The experiment relay on the magnetic field induced asymmetry out of equilibrium. I will review its theoretical analysis [5] and then I will point out that a quantitative disagreement between the theory and the experiment still remains.
[1] YU, D. S. Golubev, M. Marthaler, K. Saito, T. Fujisawa, Gerd Schon, Phys. Rev. B 81, 125331 (2010); B. Kung, C. Rossler, M. Beck, M. Marthaler, D. S. Golubev, YU, T. Ihn, K. Ensslin, Phys. Rev. X 2, 011001 (2012), J. Appl. Phys. 113, 136507 (2013).
[2] S. Nakamura, Y. Yamauchi, M. Hashisaka, K. Chida, K. Kobayashi, T. Ono, R. Leturcq, K. Ensslin, K. Saito, Y. Utsumi, and A. C. Gossard, Phys. Rev. Lett. 104, 080602 (2010); Phys. Rev. B 83, 155431 (2011).
[3] D. S. Golubev, M. Marthaler, YU, Gerd Schon, Phys. Rev. B 84, 075323 (2011).
[4] YU, D. S. Golubev, M. Marthaler, T. Fujisawa, Gerd Schon in 'Perspective of Mesoscopic Physics', edited by A. Aharony and O. Entin-Wohlman, (World Scientific, Singapore, 2010) pp. 397-414.
[5] K. Saito, and Y. Utsumi, Phys. Rev. B 78, 115429 (2008); Y. Utsumi, and K. Saito, Phys. Rev. B 79, 235311 (2009). About the speaker: 2001 Graduate School of Information Sciences, Tohoku University, PhD supervised by H. Ebisawa
2002 Postdoc, Max-Planck-Institut fuer Mikrostrukturphysik, Halle, Patrick Bruno Group
2004 Postdoc, Universitaet Karlsruhe, Gerd Schoen Group
2005 Postdoc, Condensed Matter Theory Laboratory, RIKEN, Furusaki Group
2007 Assistant Professor, Kato Group Division of Condensed Matter Theory, Institute for Solid State Physics, University of Tokyo
2010 Associate professor, Department of Physics Engineering, Faculty of Engineering, Mie University