Wilhelm Killing Kolloquium: Prof. Dr. Julian Fischer (IST, Klosterneuburg): Minimal surfaces in random environments: Quantitative homogenization, superconcentration, and applications in fracture mechanics
Thursday, 23.07.2026 14:15 im Raum M4
Minimal surfaces in a random environment arise naturally in the homogenization of models in fracture mechanics. They also are one of the natural higher-dimensional generalizations of planar first-passage percolation, the problem of finding the shortest path in a random environment. Under suitable assumptions on the probability distribution - assuming in particular statistical isotropy of the random medium -, we establish an algebraic rate of convergence for the energy of the minimal surface dividing a box $(-R,R)^d$ in the limit $R\rightarrow \infty$. We also prove a superconcentration principle for energy fluctuations in up to four ambient spatial dimensions: Energy fluctuations of the minimal surface are suppressed, as compared to the the energy fluctuations of a fixed surface like $(-R,R)^{d-1} \times \{0\}$. We discuss possible implications of the superconcentration principle concerning the accuracy of variational models for fracture in the setting of heterogeneous media.
joint works with Antonio Agresti, Nicolas Clozeau, Assylbek Olzhabayev, Christian Wagner
Angelegt am 06.07.2026 von Claudia Lückert
Geändert am 07.07.2026 von Claudia Lückert
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Perfectoid algebras and spaces are fundamental objects in modern p-adic geometry. However, many of the foundational results about them are only true "up to almost mathematics". By contrast, passing to Banach ultraproducts can eliminate this ?almost?. Our aim is to identify the structural properties of these Banach ultraproducts that make this possible. Joint work in progress with Franziska Jahnke.
Angelegt am 17.07.2026 von Alexander Domke
Geändert am 17.07.2026 von Alexander Domke
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