Special Microscopic-states-basis Formulation of Macroscopic Structure for Thermodynamic Systems

For classical system under constant composition, macroscopic structure in thermodynamically equilibrium state can be determined through the so-called canonical average, including sum over possible microscopic states on phase space. Although a set of microscopic structure dominantly contributing to equilibrium properties should depend on temperature and many-body interactions, we recently clarify that at high temperature, they are universally characterized by a single special microscopic state (which we call projection state: PS), whose structure can be known a priori without any thermodynamic information. Here we extend this approach to find additional special microscopic states, enabling us to characterize equilibrium structures for lower-temperature region above transition temperature. The concept of our approach will lead to a new paradigm; the formulation of macroscopic properties by special microscopic states basis.