Research topics in our group cover various phenomena observed in nonequilibrium systems, complex systems or disordered systems. We investigate them by theories based on statistical mechanics and computer simulations. Fukuda’s main interest lies in soft condensed matter, especially liquid crystals, and Matsui studies glass transition and supercooled liquids.

Soft Condensed Matter

Self-organized structures and dynamics of liquid crystals

We study various self-organized structures and dynamics of liquid crystals, mainly by numerical calculations based on continuum theories. Research topics of interest include, but are not limited to, exotic phases known as cholesteric blue phases, liquid crystal colloids (in part collaboration with Prof. Yasuyuki Kimura in our Department), and liquid crystals in contact with sinusoidal grooves. Structure of topological defects in liquid crystals is a major subject of interest.

Optical properties of ordered structures in soft matter

Soft materials often exhibit self-organized structures whose periodicity is of the order of the wavelength of visible light. We investigate the properties of such structures as photonic crystals, and also how they can be observed by optical means such as confocal microscopy.

Field theory of polymeric systems

From a microscopic model of semiflexible chains with bending elasticity, we made use of a field theory to derive the free energy functional and the equations of motion for compositional and orientational order parameters of the polymer component. We studied the coupling between phase separation and orientational ordering in the time evolution of these two order parameters.

Glass transition and supercooled liquids

Poly-amorphism and crystalization

We are interested in a model monatomic system, which is crystallized under cooling at high pressure and vitrified under cooling at low pressure. Using molecular dynamics simulation, we are calculating the T-P diagram and expoloring the boarder between glass and crystalline in middle range of pressure.

Slowing dynamics near the glass transition

We aim to understand the glass transition at the microscopic point of view; molecules are mostly trapped in cages formed by their surrownding molecules, which cause the diffusion coefficient decreasing and anomalous in highly supercooled liquids. Occasionally molecules hop to the neighbor's site and the neighbor do in the same way. These motions are collective and intermittent.

Social physics

Non-self-averaging properties in economic phenomena and urn model

We investigated the properties of the master equation derived from Polya’s urn model, and obtained its rigorous solutions after continuous variable approximation. We also studied the effect of perturbations to determine under which condition the model becomes non-self-averaging. We will investigate how the effect of perturbations manifests itself in economic phenomena.