Doug Coleman ACF Abstract FY11

"Mechanical Foundations of Irreversibility in Nonequilibrium Statistical Mechanics"

Butler University Undergraduate Research Conference

Doug Coleman

Coffee creamer is readily seen to diffuse into coffee, but once mixed, is
never observed to separate back. The second law of thermodynamics describes this nonreversible event by stating that a closed system not in equilibrium will evolve until it approaches its maximum value of entropyin which case the system has reached equilibriumand its macrostate will not change. Because it is known that coffee, creamer, and all other matter is composed of elementary particles whose interactions have been shown (in part) to be calculable (at least within a statistical framework), the question can be posed whether the second law of thermodynamics is a fundamental physical law, or if it can be derived from first principles of mechanics, or perhaps with something else such as statistics. Specifically interesting is that the microscopic dynamical equations thought to govern all macroscopic systems constituents are time symmetric, implying that the reversed time evolution of any process should also be physically possible. This presentation will analyze the works of Boltzmann, Gibbs, and others who have sought to derive or qualify the second law of thermodynamics in terms of the underlying time reversible microscopic dynamics. A personally developed numerical simulation will be exhibited to illustrate the foundations and paradoxes of Boltzmanns H-theorem, and the presentation will attempt to distill the literature regarding the pursuits of nonequilibrium statistical mechanics to describe entropy increase of irreversible macroscopic phenomena.