The Arrow of Time

Since Boltzmann’s works, there is the question of explaining the arrow of time in statistical physics: While many microscopic physical theories do not know a preferred direction of time, one experiences an arrow of time in the macroscopic world. Glass shatters when it falls on the ground whereas we never see the reverse process. The usual explanations for that are based on a very special initial condition, a state of very high order which under the dynamics evolves in a natural way into a state of higher disorder. Here one can see (order \(\rightarrow \) disorder) the asymmetry in the propagation in time. This explanation, however, shifts the problem to the question of where the initial state of high order came from. In the following we will discuss different possible explanations for the emergence of a macroscopic arrow of time, in particular we will discuss an idea going back to V. A. Antonov who found that the growth in disorder can be explained without assuming a special initial condition.