Multiscale mesoscopic entropy of driven macroscopic systems (Q280706)

Summary: How do macroscopic systems react to imposed external forces? Attempts to answer this question by a general principle have a long history. The general feeling is that the macroscopic systems in their reaction to imposed external forces follow some kind of optimization strategy in which their internal structure is changed so that they offer the least possible resistance. What is the potential involved in such optimization? It is often suggested that it is entropy or entropy production. But entropy is a potential arising in thermodynamics of externally unforced macroscopic systems. What exactly shall we understand by a mesoscopic entropy of externally driven systems and how shall we find it for a specific macroscopic system?