Herbert Spohn

For his wide-ranging and highly influential work in non-equilibrium statistical physics.

After post-doc years at Yeshiva, Princeton, Rutgers, and Leuven, Herbert Spohn joined the statistical physics group at the Ludwig-Maximilians-University and later moved to a chair in mathematical physics at the Technical University, both in Munich. Spohn’s contributions cover the full spectrum from foundational rigorous work to experimentally testable predictions. In collaboration with S. Katz and J.L. Lebowitz, he introduced the field-driven ‘KLS’ lattice gas model with Ising interactions that is nowadays referred to in textbooks as the ‘standard model’ of non-equilibrium stationary states. In an earlier paper he proved the ubiquitous occurrence of long-ranged correlations, a result that rose to prominence many years later in the context of generic scale invariance and macroscopic fluctuation theory. His 1991 review article with J. Krug on stochastic growth processes set the stage for much of the subsequent work on the subject. In 2000 Spohn initiated the “second wave” of research on the one-dimensional version of the KPZproblem that continues to gain momentum to this day. The beautiful and far-reaching insight on the universality properties of this problem culminated in the publication with T. Sasamoto of the first exact solution of the one-dimensional KPZ equation. Through a multi-component version of the KPZ equation, Spohn also unified the understanding of anomalous transport in one-dimensional fluids. In 1993 Spohn settled a long-standing controversy about the dynamics of crystal surfaces below the roughening transition showing that the dynamics can be properly formulated and solved as a moving boundary problem, an observation that has been tremendously influential in theoretical and computational materials science. Jointly with J.L. Lebowitz, Spohn showed that fluctuation theorems similar to those previously established for chaotic systems arise naturally in a large class of stochastic models, a contribution that marked the beginning of the current wave of interest in generic properties of non-equilibrium stationary states. Spohn has made important contributions to kinetic theory of both particles and waves (classical and quantum), open quantum systems, Schr¨odinger operators and other topics too numerous to list here. His 1980 review article on Markovian limits related to kinetic theory and the 1991 monograph “Large scale dynamics of interacting particles” are key reference works in the field.

Herbert Spohn is professor emeritus at the Technical University Munich. Amongst other distinctions, Spohn was awarded the 2014 Georg Cantor Medal of the Association of German Mathematicians, the 2015 Poincar ́e Prize of the International Association of Mathematical Physics, and the 2017 Max Planck Medal of the German Physical Society. He received honorary doctorates from Universit ́e Paris-Dauphine and Universit ́e Paris- Diderot.