Optimal Selection of Structural Degree of Freedoms for Spceial Microscopic States to Characterize Disordered Structures

Abstract

For classical discrete systems under constant composition, statistical mechanics tells us that a set of microscopic state dominantly contributing to thermodynamically equilibrium state should depend on temperature as well as on many-body interaction (i.e. thermodynamic information), through Boltzamann factor of exp(-bE). Despite this fact, our recent study reveals that a single (and a few additional) microscopic state (called projection state: PS), whose structure can be known a priori without r equiring thermodynamic information, can universally characterize equiibrium properties for disordered states, where their sturctures depends on configurational geometry before applying many-body interaction to the system. Although mathematical condition for the structures of PS have been rigorously established, practically effective condition for constructing the stuructures, especially for which set of a finite structural degree of freedoms (SDF) should be selected for considered coordination has not been clarified so far. We here tuckle this problem, proposing a quantitative and systematic criteria for an optimal set of SDFs. The present proposal enables to effectively constructing PSs for a limited system size, and also providing new insight into which set of SDFs should generally affects equilibrium properties along a chosen coordination, without using any thermodynamic information.