Research Topics


Glass Physics : From Condensed Matters to Deep Neural Networks


In crystals, the solid states with periodic arrangements of molecules exhibit rigidity. Glasses are as disordered as liquids but rigid. The cause for the emergence of the rigidity in glasses has been recognized as a long standing, one of the most important open problems in physics. Recently mechanical properties of jammed states, i. e. densly packed states of particles with macroscopic sizes, such as colloids, emulsions and sands attracts much attention of physicists. We are studying these problems using theoretical methods such as the replicated liquid theory and numerical simulations such as molecular dynamic (MD) simulations.

Replicated liquid theory combines the density functional theory of liquids and the replica method, which has been developed in the statistical mechanical studies of disorderd systems. Quite recently it has been shown that mean-field theories which become exact in the large dimensional limit (Charbonneau-Kurchan-Parisi-Urbani-Zamponi 2014) can be constructed based on this approach. Moreover it has been shown that on top of the usual 1 step replica symmetry breaking (RSB) which accompanies the glass transition, continous RSB (Gardner's transition) takes place at higher densities approaching the jamming density and dominates the critical properties of the system around the jamming.

Our recents results: Quasi-static response of the glasses under shear around the glass and jamming transitions

We are currently investigating rheological properties of these systems performing MD simulations looking for aniticipated non-trivial effects implied by the theoretical results. Large scale MD simulations are performed using supercomputing facilities of our institute (Cybermedia Center,Osaka Univ. ), ISSP Univ. of Tokyo and Inst. for Molecular Science (IMS).

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