Hiroki IKEGAMI

Senior Research Scientist, RIKEN

Field of Specialty：

Low Temperature Physics

Topics of Research：

(B01) Novel Edge Phenomena in Spin-Triplet Superfluids

Specific Topics：

Investigations of exotic phenomena at a surface of superfluid ³He.

■ Laboratory Website　

RESEARCH

In the past, I have studied quantum phenomena such as superfluidity and nuclear magnetism in helium systems at ultra-low temperatures, especially in low dimensional systems. I have created low dimensional helium systems by confining helium atoms into restricted geometries, and have investigated quantum phenomena in such superfluid and quantum spin liquid. My recent research now focuses on the investigations of properties of surface charges formed at a free surface of superfluid helium, investigations of surface quantum phenomena of the superfluid ³He using the surface charges, and basic studies towards implementation of quantum information devices using the surface electrons.

In this project, I will detect surface bound states and exotic topological defects formed at a free surface of superfluid ³He. ³He-B phase is a time-reversal-invariant topological superfluid, and bound states would be formed at a surface. The surface bound states are expected to be formed by Majorana fermions. In contrast, ³He-A phase is a superfluid with broken time-reversal symmetry. At a surface, exotic topological defects are expected to be formed. I plan to detect the surface bound states and the exotic surface defects by transport measurements of ions trapped below the surface.

EDUCATION

1995

B. S. , Dept. of Applied Physics, University of Tokyo

2001

Ph. D. , Dept. of Applied Physics, University of Tokyo

PROFESSIONAL EXPERIENCE

1999-2001

Research Associate, Graduate School of Arts and Sciences, University of Tokyo

2001-2007

Research, Scientist, RIKEN

2004-2008

Researcher, PRESTO, JST

2007-Present

Senior Research Scientist, RIKEN

HONORS AND AWARDS

2009

Young Scientist Award of Physical Society of Japan

SELECTION OF PUBLICATIONS

"Chiral Symmetry Breaking in Superfluid ³He-A",
H. Ikegami, Y. Tsutsumi, K. Kono,
Science 341, 1236509-1-5 (Jul. 2013).

"Evidence for Reentrant Melting in a Quasi-One-Dimensional Wigner Crystal",
H. Ikegami, H. Akimoto, D. G. Rees, and K. Kono,
Phys. Rev. Lett. 109, 236802(1)-(5) (2012).

"Melting of a quasi-one-dimensional Wigner crystal: Electrons on superfluid ⁴He in a narrow channel",
H. Ikegami, H. Akimoto, and K. Kono,
Phys. Rev. B 82, 201104(R) (1)-(4) (2010).

"Nonlinear Transport of the Wigner Solid on Superfluid ⁴He in a Channel Geometry",
H. Ikegami, H. Akimoto, and K. Kono,
Phys. Rev. Lett. 102, 046807(1)-(4) (2009).

"Superfluidity of ⁴He in Nano-Size Channels",
H. Ikegami, Y. Yamato, T. Okuno, J. Taniguchi, N. Wada, S. Inagaki, and Y. Fukushima,
Phys. Rev. B 76, 144503(1)-(9) (2007).

"Texture of Superfluid ³He Probed by a Wigner Solid",
H. Ikegami and K. Kono,
Phys. Rev. Lett. 97, 165303(1)-(4) (2006).

"Possible One-Dimensional ³He Quantum Fluid Formed in Nanopores",
J. Taniguchi, A. Yamaguchi, H. Ishimoto, H. Ikegami, T. Matsushita, N. Wada, S.M. Gatica, M.W. Cole, F. Ancilotto, S. Inagaki, and Y. Fukushima,
Phys. Rev. Lett. 94, 065301(1)-(4) (2005).

"⁴He Bose Fluids Formed in One-dimensional 18Å-diameter Pores",
N. Wada, J. Taniguchi, H. Ikegami, S. Inagaki, and Y. Fukushima,
Phys. Rev. Lett. 86, 4322-4325 (2001).

"Low Temperature Magnetization of Sub monolayer ³He Adsorbed on HD Preplated Graphite",
H. Ikegami, R. Masutomi, K. Obara, and H. Ishimoto,
Phys. Rev. Lett. 85, 5146-5149 (2000).

"Competition of Multiple Spin Exchanges in Submonolayer Solid ³He",
H. Ikegami, K. Obara, D. Ito, and H. Ishimoto,
Phys. Rev. Lett. 81, 2478-2481 (1998).