Introduction:

I am a research scientist working on condensed matter theory. I am broadly interested in:
  • strongly correlated electron systems
  • quantum spin systems
  • quantum magnetism
  • frustration
  • itinerant ferromagnetism
  • spin and heat transport
  • computational physics
  • quantum computation

More specifically, I have studied spin-orbital ordering and its dynamics in strongly correlated electron systems with orbital degeneracy, spin nematics in frustrated quantum spin systems, quantum phase transition and magnetic excitation in low-dimensional quantum spin systems, and extended Nagaoka ferromagnetism. I have tackled these research subjects by exploiting various numerical methods such as DMRG, time-dependent DMRG, dynamical DMRG, exact diagonalization, thermal pure quantum state, and QMC loog algorithm.

Topics:

JPS Hot Topics
"Quantum Phase Transition and Magnetic Excitation in the S=1/2 Ising-like Antiferromagnetic Chain CsCoCl3 in Transverse Magnetic Fields"
Shojiro Kimura, Hiroaki Onishi, Yasuo Narumi, Kouichi Okunishi, Masayuki Hagiwara, Koichi Kindo, and Hikomitsu Kikuchi
J. Phys. Soc. Jpn. 94, 124703 (2025).
The paper is introduced in JPS Hot Topics 6, 002.

JPSJ Papers of Editors' Choice & JPS Hot Topics
"Magnetic Excitation in the S=1/2 Ising-like Antiferromagnetic Chain CsCoCl3 in Longitudinal Magnetic Fields Studied by High-field ESR Measurements"
Shojiro Kimura, Hiroaki Onishi, Kouichi Okunishi, Mitsuru Akaki, Yasuo Narumi, Masayuki Hagiwara, Koichi Kindo, and Hikomitsu Kikuchi
J. Phys. Soc. Jpn. 92, 094701 (2023).
The paper is introduced in JPS Hot Topics 3, 039.

JPSJ Papers of Editors' Choice
"Magnetic Excitations of Spin Nematic State in Frustrated Ferromagnetic Chain"
Hiroaki Onishi
J. Phys. Soc. Jpn. 84, 083702 (2015).

Contact:

Research Group for Spin-Energy Science,
Advanced Science Research Center,
Japan Atomic Energy Agency,
Tokai, Ibaraki 319-1195, JAPAN
 〒319-1195 茨城県那珂郡東海村大字白方2番地4
日本原子力研究開発機構
先端基礎研究センター
スピン-エネルギー科学研究グループ

E-mail: onishi.hiroaki [-AT-] jaea.go.jp
Access: English / Japanese