Researcher Information

Jun Ohara

Lecturer

Various optical phenomena in correlated electron
systems

Department of Physics, Condensed Matter Physics

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Theme

Employing Hartree-Fock approximation, exact diagonalization, group theory, spin-wave theory, and so on, we reveal ultrafast photoinduced dynamics in strongly-correlated electron systems and inelastic dynamic responses of geometrically frustrated magnets.

Department of Physics, Condensed Matter Physics

Jun Ohara

Lecturer

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What made you decide to become a researcher?

I used to see special effect movies when I was a child. A “physicist”, who developed weapons and tactics to defeat villains, often appeared in these movies. I yearned to become such a “physicist”. After becoming a real physicist, I investigate various properties of condensed matters based on quantum and statistical mechanics.

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What is the research theme that you are currently focusing on?

An electron in an insulator behaves as a tiny magnet (spin). These spins interact with each other. For example, when the local interaction between two spins favors a pair of parallel spins (Fig.1A), all the spins are likely to be oriented in the same direction (ferromagnetism) and this spin structure is globally stabilized. When the locally and globally stable structures are incompatible with each other (Fig.1B), however, unexpected physical properties may be seen. We investigate novel magnetism caused by such “frustration“ based on quantum statistical mechanics. Theoretical calculations of inelastic light or neutron scattering in the frustrated magnets may stimulate experimental observation. We also develop both numerical and analytical methods.

Non-frustrated (A) and frustrated (B) spin systems.
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Please tell us about yourself; things you are good at, your favorites, hobbies, and daily routines.

I like sports, especially soccer. I used to play soccer with my friends when I was a university student. Several teams joined us and private league matches were held. Now I get into road cycling. I often go cycling along a river and coast on sunny days. There are many recommended cycling courses in Hokkaido.

A country road in summer at Hokkaido.