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Members Profile

Ryuji Nomura

Ryuji Nomura

Assistant Professor, Department of Physics, Tokyo Institute of Technology

Specific
Topics:
Topological quantum criticality of superfluid 3He by controlling magnetic fields and particle correlations

E-mail : nomura.r.aa[at]m.titech.ac.jp

RESEARCH

Superfluid 3He is the established spin-triplet p-wave fermionic condensate. It is drawing a renewed interest recently, since theorists pointed out it is a time-reversal invariant topological superfluid. I have been studying the surface bound states of superfluid 3He B-phase, which are the Majorana fermions formed due to the bulk-edge correspondence. On a wall of weak disorder, Majorana cone was detected by the transverse acoustic wave impedance measurement. On a wall of higher disorder, I revealed a peculiar behavior of the surface density of states which reflects an anomalous scattering property of Majorana fermions.

Majorana fermions in zero magnetic field without interaction have been studied by the transverse acoustic impedance. We will extend this measurement in magnetic field at higher pressures in order to examine their topological stabilities and the mass acquisition process.

EDUCATION

1991
Bachelor of Science, Kyoto University
2000
Ph.D. (Physics), Kyoto University

PROFESSIONAL EXPERIENCE

1998-2000
Research fellow, Northwestern University
2000-2007
Research associate, Graduate School of Science, Tokyo Institute of Technology
2007-Present
Assistant Professor, Department of Physics, Tokyo Institute of Technology

HONORS AND AWARDS

2007
Young Scientist Award of Physical Society of Japan
2013
A research encouragement award for young researchers of Tokyo Tech. department of science, 2012
2013
18th Outstanding Paper Award of the Physical Society of Japan

SELECTION OF PUBLICATIONS

"Crystallization of 4He in Aerogel via Mass Flow from Surrounding Solid 4He"
H. Matsuda, A. Ochi, R. Isozaki, S. Minami, R. Nomura, J. Pollanen, W. P. Halperin, and Y. Okuda
Physical Review B 94, 024509-1-7 (Jul. 2016)
DOI: 10.1103/PhysRevB.94.024509

"Control of the wetting properties of 4He crystals in superfluid"
T. Takahashi, H. Minezaki, A. Suzuki, K. Obara, K. Itaka, R. Nomura, and Y. Okuda
Physical Review E 93, 052806-1-6 (May. 2016)
DOI: 10.1103/PhysRevE.93.052806

"Equilibrium Shape of 4He Crystal under Zero Gravity below 200 mK"
T. Takahashi, H. Ohuchi, R. Nomura, and Y. Okuda
Science Advances 1, e1500825-1-5 (Oct. 2015)
DOI: 10.1126/sciadv.1500825

"Transverse Acoustic Impedance of Superfluid 3He B Phase in Weak Magnetic Fields"

K. Akiyama, M. Wasai, M. Mashino, T. Nakao, S. Murakawa, R. Nomura, and Y. Okuda
Journal of the Physical Society of Japan 84, 065001-1-2 (May. 2015)
DOI: 10.7566/JPSJ.84.065001

"Spin-Dependent Acoustic Response in the nonunitary A1 and A2 Phases of Superfluid 3He under High Magnetic Fields"
S. Murakawa, A. Yamaguchi, M. Arai, M. Wasai, Y. Aoki, H. Ishimoto, R. Nomura, Y. Okuda, Y. Nagato, S. Higashitani, and K. Nagai
Physical Review Letters 114, 105304-1-4 (Mar. 2015)
DOI: 10.1103/PhysRevLett.114.105304

"Falling 4He Crystals in Superfluid"
R. Nomura, T. Yoshida, A. Tachiki, and Y. Okuda
New Journal of Physics 16. 113022-1-9 (Nov. 2014)
DOI: 10.1088/1367-2630/16/11/113022

"Surface Majorana Cone of the Topological Superfluid 3He B phase"
R. Nomura, S. Murakawa, M. Wasai, K. Akiyama, T. Nakao, and Y. Okuda
Physics E 55, 42-47 (Jan. 2014)
DOI: 10.1016/j.physe.2013.06.006

"Thermal and Quantum Nucleation of 4He Crystals in Aerogel"
H. Matsuda, A. Ochi, R. Isozaki, R. Masumoto, R. Nomura, and Y. Okuda
Physical Review E 87, 030401(R)-1-4 (Mar. 2013)
DOI: 10.1103/PhysRevE.87.030401

"Ripening of Splashed 4He Crystals by Acoustic Waves with and without Gravity"
T. Takahashi, H. Ohuchi, R. Nomura, and Y. Okuda
New Journal of Physics 14, 123023-1-11 (Dec. 2012).
DOI: 10.1088/1367-2630/14/12/123023

"Surface Andreev bound states of superfluid 3He and Majorana Fermions"
Y. Okuda and R. Nomura
Journal of Physics: Condensed Matter 24, 343201-1-19 (Aug. 2012). Topical Review

DOI: 10.1088/0953-8984/24/34/343201

"Strong suppression of the Kosterlitz-Thouless transition in a 4He film under high pressure"
S. Murakawa, M. Wasai, K. Akiyama, Y. Wada, Y. Tamura, R. Nomura and Y. Okuda
Physical Review Letters 108, 025302-1-4 (Jan. 2012).
DOI: 10.1103/PhysRevLett.108.025302

"Surface Majorana Cone of the Superfluid 3He B Phase"
S. Murakawa, Y. Wada, Y. Tamura, M. Wasai, M. Saitoh, Y. Aoki, R. Nomura, Y. Okuda, Y. Nagato, M. Yamamoto, S. Higashitani, and K. Nagai
Journal of the Physical Society of Japan 80, 013602-1-4 (Dec. 2011).

DOI: 10.1143/JPSJ.80.013602

"New anomaly in the transverse acoustic impedance of superfluid 3He-B with a wall coated by several layers of 4He"
S. Murakawa, Y. Tamura, Y. Wada, M. Wasai, M. Saitoh, Y. Aoki, R. Nomura, Y. Okuda, Y. Nagato,M. Yamamoto, S. Higashitani, and K. Nagai,
Physical Review Letters 103, 155301-1-4 (Oct. 2009).
DOI: 10.1103/PhysRevLett.103.155301

"Broadening of the surface Andreev bound states band of superfluid 3He-B on a partially specular wall"
Y. Wada, S. Murakawa, Y. Tamura, M. Saitoh, Y. Aoki, R. Nomura, and Y. Okuda,
Physical Review B 78, 214516-1-5 (Dec. 2008).
DOI: 10.1103/PhysRevB.78.214516

"Competition between thermal fluctuations and disorder in the crystallization of 4He in aerogel"
R. Nomura, A. Osawa, T. Mimori, K. Ueno, H. Kato, and Y. Okuda,
Physical Review Letters 101, 175703-1-4 (Oct. 2008).
DOI: 10.1103/PhysRevLett.101.175703

"Observation of Surface Andreev Bound States of Superfluid 3He by Transverse Acoustic Impedance Measurements"
Y. Aoki, Y. Wada, M. Saitoh, R. Nomura, Y. Okuda, Y. Nagato, M. Yamamoto, S. Higashitani, and K. Nagai,
Physical Review Letters 95, 075301-1-4 (Aug. 2005).
DOI: 10.1103/PhysRevLett.95.075301

“Interface Motion and Nucleation of Solid Helium-4 Induced by Acoustic Waves"
R. Nomura, Y. Suzuki, S. Kimura, and Y. Okuda,
Physical Review Letters 90, 075301-1-4 (Feb. 2003).
DOI: 10.1103/PhysRevLett.90.075301