The emergence of irreversibility

Many observable processes can only happen in one direction and not the other. Thus, an ice cube that floats in a glass of water will melt, but from water will never spontaneously form an ice cube. However, the physics laws of the microscopic world do not give preference to a particular direction of time. This mismatch is the problem of irreversibility, which has been one of the most important issues of physics since the 19th century. In this lecture we will look at the conceptual and mathematical developments surrounding this problem (which led to a Field Medal in 2026!) and wonder how well we understand today the emergence of irreversibility from reversible microscopic laws.

Nino Dekkers is pursuing a PhD in mathematics at Eindhoven University of Technology and works on the foundations of statistical physics.