From time-symmetric microscopic dynamics totime-asymmetric macroscopic behavior: an overview

摘要

Let me start by stating clearly that I am not going to discuss here – much less claim toresolve – the many complex issues, philosophical and physical, concerning the natureof time, from the way we perceive it to the way it enters into the space-time structure inrelativistic theories. I will also not try to philosophize about the "true" nature of prob-ability. My goal here, as in my previous articles [1], [2] on this subject, is much moremodest.' I will take (our everyday notions of) space, time and probability as primitiveundefined concepts and try to clarify the many conceptual and mathematical problemsencountered in going from a time symmetric Hamiltonian microscopic dynamics to atime asymmetric macroscopic one, as given for example by the diffusion equation. Iwill also take it for granted that every bit of macroscopic matter is composed of anenormous number of quasi-autonomous units, called atoms (or molecules).