Foundations of Physics

, Volume 34, Issue 1, pp 1–20

Time Evolution in Macroscopic Systems. I. Equations of Motion

  • W. T. GrandyJr.

DOI: 10.1023/B:FOOP.0000012007.06843.ed

Cite this article as:
Grandy, W.T. Foundations of Physics (2004) 34: 1. doi:10.1023/B:FOOP.0000012007.06843.ed


Time evolution of macroscopic systems is re-examined primarily through further analysis and extension of the equation of motion for the density matrix ρ(t). Because ρ contains both classical and quantum-mechanical probabilities it is necessary to account for changes in both in the presence of external influences, yet standard treatments tend to neglect the former. A model of time-dependent classical probabilities is presented to illustrate the required type of extension to the conventional time-evolution equation, and it is shown that such an extension is already contained in the definition of the density matrix.

nonequilibrium statistical mechanics time-dependent probabilities 

Copyright information

© Plenum Publishing Corporation 2004

Authors and Affiliations

  • W. T. GrandyJr.
    • 1
  1. 1.Department of Physics & AstronomyUniversity of WyomingLaramie

Personalised recommendations