Grand Projection State: A Single Microscopic State to Determine Free   Energy
  Recently, we clarify connection of spatial constraint and equilibrium macroscopic properties in disordered states of classical system under the fixed composition; namely few special microscopic states, independent of constituent elements, can describe macroscopic properties. In this study, we extend our developed approach to composition-unfixed system. Through this extension in binary system, we discover a single special microscopic state to determine not only composition but also Helmholtz free energy measured from unary system, which has not been described by a single state. 
Tetsuya Taikei, Tetsuya Kishimoto, Kazuhito Takeuchi, and Koretaka   Yuge
cond-mat.dis-nn