# Nonequilibrium physics – an introduction

**PD Dr. Falko Zieber****t**

Lecture: Wed 12-14 in SR III

Starting date: 19.10.2016

Exercises: 1h, to be announced

**Contents:**

We will give an introduction to nonequilibrium physics, both on the macroscopic (thermodynamic) and the microscopic (kinetic) level.

We will start by generalizing equilibrium thermodynamics to spatial degrees of freedom. By allowing for small currents (of heat, or particles, for instance), the theory of linearly irreversible thermodynamics will be developed. A major insight will be the occurrence of cross-coupling effects, like the Peltier and Soret effect, obeying important symmetries (Onsager relations, Nobel Prize in Chemistry 1968). The occurrence of instabilities (I. Prigogine, Nobel Prize in Chemistry 1977) will also be discussed.

We will then switch to the microscopic scale and derive the famous Boltzmann equation, the foundation of transport theory. We will solve it by several approximation methods and use it to derive macroscopic balance equations, yielding a microscopic foundation of the processes described in the first part of the lecture.

Finally, we will discuss few current research topics, like the use of Boltzmann-type equations in the modeling of 'active' systems (collective motion of animals, dynamics of cellular extracts) and the occurrence of nonequilibrium phase transitions in boundary-driven transport (asymmetric exclusion processes).

**Prerequisites: **

equilibrium thermodynamics

**Literature:**

- S. De Groot & P. Mazur : Grundlagen der Thermodynamik irreversibler Prozesse
- L. Reichl : A modern course in statistical physics
- Landau & Lifshitz Vol 10: Kinetics