For its Summer 2026 term, the STOCHASTICA SNIP seminar will be held online every two weeks starting on May 13.  Talks of 30-45 minutes will be followed by 15-30 minutes of open discussion. Initially, seminars will be focused on introducing new problems and applications, to stimulate further discussions and ideas within individual working groups.  

The final seminar will be given by Prof. Dr. Alexandra Blessing (Neamtu), University of Konstanz.

Renormalization destroys a finite-time bifurcation in the $\Phi^4_2$ equation

We study the singular $\Phi^4_2$ equation at a pitchfork bifurcation of the underlying deterministic dynamics. To this aim, we linearize the SPDE along its stationary solution and show that the support of its finite-time Lyapunov exponents (FTLEs) is the real line, regardless of the bifurcation parameter and in sharp contrast to the non-singular $\Phi^4_1$ equation. The proof relies on a support theorem for the stationary solution and its renormalized square. This talk is based on a joint work with Nicolas Perkowski and Chara Zhu.