André Schlichting

News and Updates

Preprint: Maximal monotonicity and contraction semigroup for the quantum drift-diffusion (Derrida–Lebowitz–Speer–Spohn) equation

17 August 2026

Together with Daniel Matthes and Giuseppe Savaré, we study the quantum drift-diffusion, or Derrida–Lebowitz–Speer–Spohn (DLSS), equation for a nonnegative density ϱ\varrho on a bounded convex domain with Neumann boundary conditions, in the square-root variable u=ϱu=\sqrt{\varrho} . We show that the DLSS operator, defined and monotone on smooth strictly positive functions, admits a unique maximal monotone extension in L2(Ω)L^{2}(\Omega) , explicitly given by the minimal (defect-free) operator plus the normal cone of the positivity constraint.

Preprint: Formation of clusters and coarsening in weakly interacting diffusions

20 October 2025

Together with Nicolai Gerber, Rishabh Gvalani, Martin Hairer and Greg Pavliotis, we study the clustering behavior of weakly interacting diffusions under the influence of sufficiently localized attractive interaction potentials on the one-dimensional torus. We describe how this clustering behavior is closely related to the presence of discontinuous phase transitions in the mean-field PDE. For local attractive interactions, we employ a new variant of the strict Riesz rearrangement inequality to prove that all global minimizers of the free energy are either uniform or single-cluster states, in the sense that they are symmetrically decreasing.

Now published in Nonlinearity 39(7), 075023 (2026).

Preprint: Derivation of the fourth-order DLSS equation with nonlinear mobility via chemical reactions

8 October 2025

Together with Alexander Mielke and Artur Stephan, we provide a derivation of the fourth-order DLSS equation based on an interpretation as a chemical reaction network. We consider the rate equation on the discretized circle for a process in which pairs of particles occupying the same site simultaneously jump to the two neighboring sites; the reverse process involves pairs of particles at adjacent sites simultaneously jumping back to the site located between them. Depending on the rates, in the vanishing-mesh-size limit we obtain either the classical DLSS equation or a variant with nonlinear mobility of power type.

Now accepted in SIAM Journal on Mathematical Analysis.

Preprint: Existence and Non-existence for Continuous Generalized Exchange-Driven Growth model

5 September 2025

Together with Chun Yin Lam, after the derivation of the continuous generalized exchange-driven growth model in arXiv:2503.21572, we continue the study of the existence and uniqueness of solutions for kernels with superlinear growth at infinity and singularity at the origin. Moreover, we show the non-existence of solutions for kernels with sufficiently rapid growth. The latter result is shown via the finite-time gelation and instantaneous gelation in the sense of moment blow-up.

Preprint: Convergence of a stochastic particle system to the continuous generalized exchange-driven growth model

27 March 2025

Together with Chun Yin Lam, we study the continuous generalized exchange-driven growth model (CGEDG) is a system of integro-differential equations describing the evolution of cluster mass under mass exchange. The rate of exchange depends on the masses of the clusters involved and the mass being exchanged. This can be viewed as both a continuous generalization of the exchange-driven growth model and a coagulation-fragmentation equation that generalizes the continuous Smoluchowski equation.

Now published in Electron. J. Probab. 31(50), 1-29 (2026).

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