The concept of entropy in nonequilibrium macroscopic systems is investigated in the light of an extended equation of motion for the density matrix obtained in a previous study. It is found that a time-dependent information entropy can be defined unambiguously, but it is the time derivative or entropy production that governs ongoing processes in these systems. The differences in physical interpretation and thermodynamic role of entropy in equilibrium and nonequilibrium systems is emphasized and the observable aspects of entropy production are (...) noted. A basis for nonequilibrium thermodynamics is also outlined. (shrink)

The results of two recent articles expanding the Gibbs variational principle to encompass all of statistical mechanics, in which the role of external sources is made explicit, are utilized to further explicate the theory. Representative applications to nonequilibrium thermodynamics and hydrodynamics are presented, describing several fundamental processes, including hydrodynamic fluctuations. A coherent description of macroscopic relaxation dynamics is provided, along with an exemplary demonstration of the approach to equilibrium in a simple fluid.

An elementary-particle picture developed primarily by Barut as an alternative to the standard model is re-examined. This model is formulated on the basis of strong short-range magnetic interactions among the stable particles (p, e−, v) and at present is able to account qualitatively for most of the known phenomena.

The past decade has witnessed significant advances in our understanding of nonlinear systems, both theoretically and experimentally. In turn, these insights have led to applications over a broad range of subjects, as well as to new interpretations of complex behavior. Inevitably, it seems, there has been a concomitant rush to re-interpret various well-understood aspects of thermodynamic behavior in manybody systems by means of these mechanisms. It is perhaps useful, therefore, to examine these notions critically, and in doing so we are (...) able to illuminate somewhat the origins of, and motivations for, various dubious descriptions of these systems. Among other things, one notices in such discussions an unfortunate focus on “randomness,” rather than on the actual role of probabilities in describing the phenomena. Although valuable insights into some areas of complex behavior have arisen from studies of so-called “deterministic chaos,” we can detect no influence they may have on the predictions of statistical mechanics, and thus conclude that they are of little relevance to the thermodynamic behavior of large systems. (shrink)