Christian Wagner Successfully Defends PhD on Randomness in Mathematical Models

Christian Wagner, a PhD student in Felix Otto’s group, has successfully defended his doctoral thesis “On the Influence of Quenched Randomness on the Large-Scale Behavior in Drift-Diffusion Equations and Variational Interface Models.” Congratulations!

Christian’s research lies at the intersection of analysis and probability theory. Many of the problems he tackled rely on tools and concepts from stochastic homogenization.

He describes his work as follows:
“In my dissertation I studied three models sharing the common feature that their behaviour is driven by a component of disorder, which, in the language of statistical mechanics, is referred to as quenched randomness. For a typical realization, this type of randomness leads to averaging on large scales. Hence the models develop an effective macrosopic behaviour. For instance, the “diffusion in the curl of the two-dimensional Gaussian free field” that I considered in my thesis is advected by a random drift leading to super-diffusive and, as shown as part of my work as a PhD student, intermittent behaviour. In my thesis I am particularly interested in critical situations, where at first glance deterministic effects and the influence of the randomness are in balance. The aforementioned problem is a prominent example of such a situation.”

Originally from Magdeburg, Christian completed his B.Sc. and M.Sc. in Mathematics at Otto-von-Guericke-Universität Magdeburg before joining the MPI in Leipzig in 2021 for his doctoral studies. In March 2025, he began a postdoctoral position as an ISTA Fellow in Julian Fischer’s group at the Institute of Science and Technology Austria (ISTA).

We warmly congratulate Christian and wish him all the best for his academic and personal journey.