Project
outline
Head
InvestigatorShuichi
Murakami

New development of
material science through
quasiparticle hybridization
Quasiparticles are quantum mechanical entities that behave like particles in materials. Complex physical phenomena can be understood as the motion of a small number of quasiparticles. Because different quasiparticles have different length and time scales, they usually behave independently. If we can hybridize quasiparticles despite these different scales, it will lead to new properties and functions of materials. We call such hybridized quasiparticles “chimera quasiparticles” in this research area. The aim of this research area is to discover new properties and functions by designing chimera quasiparticles through the introduction of various schemes to overcome the scale differences. Researchers in the fields of spintronics, metamaterials, and chiral molecules come together to open a new frontier of science of chimera quasiparticles in a cross-disciplinary manner.
Project
outline
The project will bring about new developments in materials science by creating “chimeras” (hybrids) by “chemically reacting” a wide variety of quasiparticles and clarifying the physical properties and functionality of the chimera quasiparticles. In order to hybridize various quasiparticles, which have been studied individually in the past, it is essential to introduce various new schemes, such as artificial structures, material and molecular design, and symmetry design via interdisciplinary approaches.






New quasiparticles created by hybridizing various types of quasiparticles are called chimera quasiparticles. However, in most cases, quasiparticles behave independently of each other due to differences in time and space scales. In this research area, we will create “chimeras” (hybrids) by “chemical reactions” between quasiparticles that have been studied independently, transcending differences in scale (scale transcendence), and clarify the physical properties and functions of the chimera quasiparticles.
In order to produce a chimera quasiparticle, it is necessary to match the time period (time scale) and spatial wavelength (space scale) of both quasiparticles, but quasiparticles usually have different scales, preventing realization of chimera quasiparticles. In order to produce chimera quasiparticles, “scale transcendence” beyond the original scale of the quasiparticles is essential.
New time and space scales can be added by introducing various structures to promote hybridizations of quasiparticles. Artificial structures such as metamaterials can be utilized in the macroscopic approach, while precisely designed materials and molecules can be utilized in the microscopic approach. Furthermore, the symmetry design of structures is critically important from a broader perspective.

Quasiparticle coupling can give quasiparticles new functions and properties. Hybridization with quasiparticles that are highly controllable by an external field enables selective or local excitation of various quasiparticles. Hybridization with quasiparticles that show nonreciprocity enables one-way propagation. The chimera quasiparticles are useful to realize gigantic nonlinear phenomena.
