Publications
Monographs

P. Friz, W. König, Ch. Mukherjee, S. Olla, eds., Probability and Analysis in Interacting Physical Systems. In Honor of S.R.S. Varadhan, Berlin, August, 2016, 283 of Springer Proceedings in Mathematics & Statistics, Springer, 2019, pp. 1294, (Monograph Published), DOI https://doi.org/10.1007/9783030153380 .
Articles in Refereed Journals

F. Flegel, M. Heida, M. Slowik, Homogenization theory for the random conductance model with degenerate ergodic weights and unboundedrange jumps, Annales de l'Institut Henri Poincare. Probabilites et Statistiques, 55 (2019), pp. 12261257, DOI 10.1214/18AIHP917 .
Abstract
We study homogenization properties of the discrete Laplace operator with random conductances on a large domain in Zd. More precisely, we prove almostsure homogenization of the discrete Poisson equation and of the top of the Dirichlet spectrum. We assume that the conductances are stationary, ergodic and nearestneighbor conductances are positive. In contrast to earlier results, we do not require uniform ellipticity but certain integrability conditions on the lower and upper tails of the conductances. We further allow jumps of arbitrary length. Without the longrange connections, the integrability condition on the lower tail is optimal for spectral homogenization. It coincides with a necessary condition for the validity of a local central limit theorem for the random walk among random conductances. As an application of spectral homogenization, we prove a quenched large deviation principle for thenormalized and rescaled local times of the random walk in a growing box. Our proofs are based on a compactness result for the Laplacian's Dirichlet energy, Poincaré inequalities, Moser iteration and twoscale convergence 
F. Flegel, M. Heida, The fractional pLaplacian emerging from homogenization of the random conductance model with degenerate ergodic weights and unboundedrange jumps, Calculus of Variations and Partial Differential Equations, Published online on 28.11.2019, DOI 10.1007/s0052601916634 .
Abstract
We study a general class of discrete pLaplace operators in the random conductance model with longrange jumps and ergodic weights. Using a variational formulation of the problem, we show that under the assumption of bounded first moments and a suitable lower moment condition on the weights, the homogenized limit operator is a fractional pLaplace operator. Under strengthened lower moment conditions, we can apply our insights also to the spectral homogenization of the discrete Lapalace operator to the continuous fractional Laplace operator. 
C. Bartsch, V. Wiedmeyer, Z. Lakdawala, R.I.A. Patterson, A. Voigt, K. Sundmacher, V. John, Stochasticdeterministic population balance modeling and simulation of a fluidized bed crystallizer experiment, Chemical Engineering Sciences, 208 (2019), 115102, DOI 10.1016/j.ces.2019.07.020 .

CH. Hirsch, B. Jahnel, Large deviations for the capacity in dynamic spatial relay networks, Markov Processes and Related Fields, 25 (2019), pp. 3373.
Abstract
We derive a large deviation principle for the spacetime evolution of users in a relay network that are unable to connect due to capacity constraints. The users are distributed according to a Poisson point process with increasing intensity in a bounded domain, whereas the relays are positioned deterministically with given limiting density. The preceding work on capacity for relay networks by the authors describes the highly simplified setting where users can only enter but not leave the system. In the present manuscript we study the more realistic situation where users leave the system after a random transmission time. For this we extend the point process techniques developed in the preceding work thereby showing that they are not limited to settings with strong monotonicity properties. 
A.D. Mcguire, S. Mosbach, G. Reynolds, R.I.A. Patterson, E.J. Bringley, N.A. Eaves, J. Dreyer, M. Kraft, Analysing the effect of screw configuration using a stochastic twinscrew granulation model, , 203 (2019), pp. 358379, DOI https://doi.org/10.1016/j.ces.2019.03.078 .

L. Andreis, A. Asselah, P. Dai Pra , Ergodicity of a system of interacting random walks with asymmetric interaction, Annales de l'Institut Henri Poincare. Probabilites et Statistiques, 55 (2019), pp. 590606.
Abstract
We study N interacting random walks on the positive integers. Each particle has drift delta towards infinity, a reflection at the origin, and a drift towards particles with lower positions. This inhomogeneous mean field system is shown to be ergodic only when the interaction is strong enough. We focus on this latter regime, and point out the effect of piles of particles, a phenomenon absent in models of interacting diffusion in continuous space. 
C. Bartsch, V. John, R.I.A. Patterson, Simulations of an ASA flow crystallizer with a coupled stochasticdeterministic approach, Comput. Chem. Engng., 124 (2019), pp. 350363, DOI 10.1016/j.compchemeng.2019.01.012 .
Abstract
A coupled solver for population balance systems is presented, where the flow, temperature, and concentration equations are solved with finite element methods, and the particle size distribution is simulated with a stochastic simulation algorithm, a socalled kinetic MonteCarlo method. This novel approach is applied for the simulation of an axisymmetric model of a tubular flow crystallizer. The numerical results are compared with experimental data. 
B. Jahnel, Ch. Külske, Gibbsian representation for point processes via hyperedge potentials, Journal of Theoretical Probability, published online on 03.11.2019 (2019), pp. 127, DOI 10.1007/s10959019009607 .
Abstract
We consider marked point processes on the ddimensional euclidean space, defined in terms of a quasilocal specification based on marked Poisson point processes. We investigate the possibility of constructing uniformly absolutely convergent Hamiltonians in terms of hyperedge potentials in the sense of Georgii [2]. These potentials are natural generalizations of physical multibody potentials which are useful in models of stochastic geometry. 
W. König, A. Tóbiás, A Gibbsian model for message routeing in highly dense multihop networks, ALEA. Latin American Journal of Probability and Mathematical Statistics, 16 (2019), pp. 211258, DOI DOI: 10.30757/ALEA.v1608 .
Abstract
We investigate a probabilistic model for routing in relayaugmented multihop adhoc communication networks, where each user sends one message to the base station. Given the (random) user locations, we weigh the family of random, uniformly distributed message trajectories by an exponential probability weight, favouring trajectories with low interference (measured in terms of signaltointerference ratio) and trajectory families with little congestion (measured by how many pairs of hops use the same relay). Under the resulting Gibbs measure, the system targets the best compromise between entropy, interference and congestion for a common welfare, instead of a selfish optimization. We describe the joint routing strategy in terms of the empirical measure of all message trajectories. In the limit of high spatial density of users, we derive the limiting free energy and analyze the optimal strategy, given as the minimizer(s) of a characteristic variational formula. Interestingly, expressing the congestion term requires introducing an additional empirical measure. 
W. König, A. Tóbiás, Routeing properties in a Gibbsian model for highly dense multihop networks, IEEE Transactions on Information Theory, 65 (2019), pp. 68756897, DOI 10.1109/TIT.2019.2924187 .
Abstract
We investigate a probabilistic model for routeing in a multihop adhoc communication network, where each user sends a message to the base station. Messages travel in hops via the other users, used as relays. Their trajectories are chosen at random according to a Gibbs distribution that favours trajectories with low interference, measured in terms of sum of the signaltointerference ratios for all the hops, and collections of trajectories with little total congestion, measured in terms of the number of pairs of hops arriving at each relay. This model was introduced in our earlier paper [KT17], where we expressed, in the highdensity limit, the distribution of the optimal trajectories as the minimizer of a characteristic variational formula. In the present work, in the special case in which congestion is not penalized, we derive qualitative properties of this minimizer. We encounter and quantify emerging typical pictures in analytic terms in three extreme regimes. We analyze the typical number of hops and the typical length of a hop, and the deviation of the trajectory from the straight line in two regimes, (1) in the limit of a large communication area and large distances, and (2) in the limit of a strong interference weight. In both regimes, the typical trajectory turns out to quickly approach a straight line, in regime (1) with equallysized hops. Surprisingly, in regime (1), the typical length of a hop diverges logarithmically as the distance of the transmitter to the base station diverges. We further analyze the local and global repulsive effect of (3) a densely populated area on the trajectories. Our findings are illustrated by numerical examples. We also discuss a gametheoretic relation of our Gibbsian model with a joint optimization of message trajectories opposite to a selfish optimization, in case congestion is also penalized 
R.I.A. Patterson, D.R.M. Renger, Large deviations of jump process fluxes, Mathematical Physics, Analysis and Geometry. An International Journal Devoted to the Theory and Applications of Analysis and Geometry to Physics, 22 (2019), pp. 21/121/32, DOI 10.1007/s1104001993184 .
Abstract
We study a system of interacting particles that randomly react to form new particles. The reaction flux is the rescaled number of reactions that take place in a time interval. We prove a dynamic largedeviation principle for the reaction fluxes under general assumptions that include massaction kinetics. This result immediately implies the dynamic large deviations for the empirical concentration.
Contributions to Collected Editions

B. Jahnel, W. König, Probabilistic methods for spatial multihop communication systems, in: Topics in Applied Analysis and Optimisation, M. Hintermüller, J.F. Rodrigues, eds., CIM Series in Mathematical Sciences, Springer, Springer International Publishing, 2019, pp. 239268.
Preprints, Reports, Technical Reports

F. DEN Hollander, W. König, R. Soares Dos Santos, The parabolic Anderson model on a GaltonWatson tree, Preprint no. 2675, WIAS, Berlin, 2020, DOI 10.20347/WIAS.PREPRINT.2675 .
Abstract, PDF (428 kByte)
We study the longtime asymptotics of the total mass of the solution to the parabolic Anderson model ( PAM) on a supercritical GaltonWatson random tree with bounded degrees. We identify the secondorder contribution to this asymptotics in terms of a variational formula that gives information about the local structure of the region where the solution is concentrated. The analysis behind this formula suggests that, under mild conditions on the model parameters, concentration takes place on a tree with minimal degree. Our approach can be applied to finite locally treelike random graphs, in a coupled limit where both time and graph size tend to infinity. As an example, we consider the configuration model or, more precisely, the uniform simple random graph with a prescribed degree sequence. 
A. Hinsen, B. Jahnel, E. Cali, J.P. Wary, Malware propagation in urban D2D networks, Preprint no. 2674, WIAS, Berlin, 2020, DOI 10.20347/WIAS.PREPRINT.2674 .
Abstract, PDF (3133 kByte)
We introduce and analyze models for the propagation of malware in pure D2D networks given via stationary CoxGilbert graphs. Here, the devices form a Poisson point process with random intensity measure λ, Λ where Λ is stationary and given, for example, by the edgelength measure of a realization of a PoissonVoronoi tessellation that represents an urban street system. We assume that, at initial time, a typical device at the center of the network carries a malware and starts to infect neighboring devices after random waiting times. Here we focus on Markovian models, where the waiting times are exponential random variables, and nonMarkovian models, where the waiting times feature strictly positive minimal and finite maximal waiting times. We present numerical results for the speed of propagation depending on the system parameters. In a second step, we introduce and analyze a counter measure for the malware propagation given by special devices called white knights, which have the ability, once attacked, to eliminate the malware from infected devices and turn them into white knights. Based on simulations, we isolate parameter regimes in which the malware survives or is eliminated, both in the Markovian and nonMarkovian setting. 
B. Jahnel, A. Tóbiás, SINR percolation for Cox point processes with random powers, Preprint no. 2659, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2659 .
Abstract, PDF (356 kByte)
Signaltointerference plus noise ratio (SINR) percolation is an infiniterange dependent variant of continuum percolation modeling connections in a telecommunication network. Unlike in earlier works, in the present paper the transmitted signal powers of the devices of the network are assumed random, i.i.d. and possibly unbounded. Additionally, we assume that the devices form a stationary Cox point process, i.e., a Poisson point process with stationary random intensity measure, in two or higher dimensions. We present the following main results. First, under suitable moment conditions on the signal powers and the intensity measure, there is percolation in the SINR graph given that the device density is high and interferences are sufficiently reduced, but not vanishing. Second, if the interference cancellation factor γ and the SINR threshold τ satisfy γ ≥ 1/(2τ), then there is no percolation for any intensity parameter. Third, in the case of a Poisson point process with constant powers, for any intensity parameter that is supercritical for the underlying Gilbert graph, the SINR graph also percolates with some small but positive interference cancellation factor. 
L. Taggi, Uniformly positive correlations in the dimer model and phase transition in lattice permutations in mathbbZ^d, d > 2, via reflection positivity, Preprint no. 2647, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2647 .
Abstract, PDF (580 kByte)
Our first main result is that correlations between monomers in the dimer model in ℤ^{d} do not decay to zero when d > 2. This is the first rigorous result about correlations in the dimer model in dimensions greater than two and shows that the model behaves drastically differently than in two dimensions, in which case it is integrable and correlations are known to decay to zero polynomially. Such a result is implied by our more general, second main result, which states the occurrence of a phase transition in the model of lattice permutations, which is related to the quantum Bose gas. More precisely, we consider a selfavoiding walk interacting with lattice permutations and we prove that, in the regime of fullypacked loops, such a walk is `long' and the distance between its endpoints grows linearly with the diameter of the box. These results follow from the derivation of a version of the infrared bound from a new general probabilistic settings, with coloured loops and walks interacting at sites and walks entering into the system from some `virtual' vertices. 
A. Hinsen, B. Jahnel, E. Cali, J.P. Wary, Phase transitions for chaseescape models on Gilbert graphs, Preprint no. 2642, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2642 .
Abstract, PDF (219 kByte)
We present results on phase transitions of local and global survival in a twospecies model on Gilbert graphs. At initial time there is an infection at the origin that propagates on the Gilbert graph according to a continuoustime nearestneighbor interacting particle system. The Gilbert graph consists of susceptible nodes and nodes of a second type, which we call white knights. The infection can spread on susceptible nodes without restriction. If the infection reaches a white knight, this white knight starts to spread on the set of infected nodes according to the same mechanism, with a potentially different rate, giving rise to a competition of chase and escape. We show welldefinedness of the model, isolate regimes of global survival and extinction of the infection and present estimates on local survival. The proofs rest on comparisons to the process on trees, percolation arguments and finitedegree approximations of the underlying random graphs. 
D. Heydecker, R.I.A. Patterson, Bilinear coagulation equations, Preprint no. 2637, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2637 .
Abstract, PDF (453 kByte)
We consider coagulation equations of Smoluchowski or Flory type where the total merge rate has a bilinear form π(y) · Aπ (x) for a vector of conserved quantities π, generalising the multiplicative kernel. For these kernels, a gelation transition occurs at a finite time t_{g} ∈ (0,∞), which can be given exactly in terms of an eigenvalue problem in finite dimensions. We prove a hydrodynamic limit for a stochastic coagulant, including a corresponding phase transition for the largest particle, and exploit a coupling to random graphs to extend analysis of the limiting process beyond the gelation time. 
CH. Hirsch, B. Jahnel, A. Tóbiás, Lower large deviations for geometric functionals, Preprint no. 2632, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2632 .
Abstract, PDF (1268 kByte)
This work develops a methodology for analyzing largedeviation lower tails associated with geometric functionals computed on a homogeneous Poisson point process. The technique applies to characteristics expressed in terms of stabilizing score functions exhibiting suitable monotonicity properties. We apply our results to clique counts in the random geometric graph, intrinsic volumes of PoissonVoronoi cells, as well as powerweighted edge lengths in the random geometric, κnearest neighbor and relative neighborhood graph. 
D.R.M. Renger, J. Zimmer, Orthogonality of fluxes in general nonlinear reaction networks, Preprint no. 2609, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2609 .
Abstract, PDF (261 kByte)
We consider the chemical reaction networks and study currents in these systems. Reviewing recent decomposition of rate functionals from large deviation theory for Markov processes, we adapt these results for reaction networks. In particular, we state a suitable generalisation of orthogonality of forces in these systems, and derive an inequality that bounds the free energy loss and Fisher information by the rate functional. 
K. Chouk, W. van Zuijlen, Asymptotics of the eigenvalues of the Anderson Hamiltonian with white noise potential in two dimension, Preprint no. 2606, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2606 .
Abstract, PDF (588 kByte)
In this paper we consider the Anderson Hamiltonian with white noise potential on the box [0,L]² with Dirichlet boundary conditions. We show that all the eigenvalues divided by log L converge as L → ∞ almost surely to the same deterministic constant, which is given by a variational formula. 
S. Jansen, W. König, B. Schmidt, F. Theil, Surface energy and boundary layers for a chain of atoms at low temperature, Preprint no. 2589, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2589 .
Abstract, PDF (529 kByte)
We analyze the surface energy and boundary layers for a chain of atoms at low temperature for an interaction potential of LennardJones type. The pressure (stress) is assumed small but positive and bounded away from zero, while the temperature goes to zero. Our main results are: (1) As the temperature goes to zero and at fixed positive pressure, the Gibbs measures for infinite chains and semiinfinite chains satisfy path large deviations principles. The rate functions are bulk and surface energy functionals. The minimizer of the surface functional corresponds to zero temperature boundary layers. (2) The surface correction to the Gibbs free energy converges to the zero temperature surface energy, characterized with the help of the minimum of the surface energy functional. (3) The bulk Gibbs measure and Gibbs free energy can be approximated by their Gaussian counterparts. (4) Bounds on the decay of correlations are provided, some of them uniform in the inverse temperature. 
A. Tóbiás, B. Jahnel, Exponential moments for planar tessellations, Preprint no. 2572, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2572 .
Abstract, PDF (276 kByte)
In this paper we show existence of all exponential moments for the total edge length in a unit disc for a family of planar tessellations based on Poisson point processes. Apart from classical such tessellations like the PoissonVoronoi, PoissonDelaunay and Poisson line tessellation, we also treat the JohnsonMehl tessellation, Manhattan grids, nested versions and Palm versions. As part of our proofs, for some planar tessellations, we also derive existence of exponential moments for the number of cells and the number of edges intersecting the unit disk. 
L. Andreis, W. König, R.I.A. Patterson, A largedeviations approach to gelation, Preprint no. 2568, WIAS, Berlin, 2019, DOI 10.20347/WIAS.PREPRINT.2568 .
Abstract, PDF (338 kByte)
A largedeviations principle (LDP) is derived for the state, at fixed time, of the multiplicative coalescent in the large particle number limit. The rate function is explicit and describes each of the three parts of the state: microscopic, mesoscopic and macroscopic. In particular, it clearly captures the well known gelation phase transition given by the formation of a particle containing a positive fraction of the system mass at time t=1. Via a standard map of the multiplicative coalescent onto a timedependent version of the ErdősRényi random graph, our results can also be rephrased as an LDP for the component sizes in that graph. Our proofs rely on estimates and asymptotics for the probability that smaller ErdősRényi graphs are connected.
Talks, Poster

A. Hinsen, Data mobility in adhoc networks: Vulnerability and security, KEIN öffentlicher Vortrag (Orange), Telecom Orange Paris, France, December 12, 2019.

A. Hinsen, IPS in telecommunication I, Workshop on Probability, Analysis and Applications (PAA), September 23  October 4, 2019, African Institute for Mathematical Sciences  Ghana (AIMS Ghana), Accra, Ghana, October 4, 2019.

A. Hinsen, IPS in telecommunication II, Workshop on Probability, Analysis and Applications (PAA), September 23  October 4, 2019, African Institute for Mathematical Sciences  Ghana (AIMS Ghana), Accra, Ghana, October 4, 2019.

A. Hinsen, Introduction to interacting particles systems (IPS), Workshop on Probability, Analysis and Applications (PAA), September 23  October 4, 2019, African Institute for Mathematical Sciences  Ghana (AIMS Ghana), Accra, Ghana, October 2, 2019.

A. Hinsen, The White Knight model  An epidemic on a spatial random network, Bocconi Summer School in Advanced Statistics and Probability, Lake Como School of Advanced Studies, Lake Como, Italy, July 8  19, 2019.

A. Hinsen, Typical Voronoi cells for Cox point processes on Manhattan grids, The International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt 2019) [The 13th Workshop on Spatial Stochastic Models for Wireless Networks (SpasWin 2019 )], June 7, 2019, Avignon, France, June 7, 2019.

T. Orenshtein, Random walks in random environment as rough paths, Probability Seminar, New York University Shanghai, Institute of Mathematical Sciences, Shanghai, China, November 26, 2019.

D.R.M. Renger, A generic formulation of a chemical reaction network from OnsagerMachlup theory, Conference to celebrate 80th jubilee of Miroslav Grmela, May 18  19, 2019, Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Prag, Czech Republic, May 19, 2019.

D.R.M. Renger, Macroscopic fluctuation theory of chemical reaction networks, Workshop on Chemical Reaction Networks, July 1  3, 2019, Politecnico di Torino, Dipartimento di Scienze Matematiche ''G. L. Lagrange``, Italy, July 2, 2019.

D.R.M. Renger, Reaction fluxes, Applied Mathematics Seminar, University of Birmingham, School of Mathematics, UK, April 4, 2019.

W. van Zuijlen, Bochner integrals in ordered vector spaces, Analysis Seminar, University of Canterbury, Department of Mathematics and Statistics, UK, March 1, 2019.

W. van Zuijlen, From periodic to Dirichlet and Neumann on boxes, 12th OxfordBerlin Young Researchers Meeting on Applied Stochastic Analysis, December 4  6, 2019, University of Oxford, Mathematical Institute, UK, December 6, 2019.

W. van Zuijlen, From periodic to Dirichlet and Neumann on boxes, Seminar Forschergruppe 2402: Research Unit  Rough paths, stochastic partial differential equations and related topics, Technische Universität Berlin, Institut für Mathematik, December 12, 2019.

W. van Zuijlen, Massasymptotics for the parabolic Anderson model in 2 d, BerlinLeipzig workshop in analysis and stochastics, January 16  18, 2019, Max Planck Institute ür Mathematik in den Naturwissenschaften, Leipzig, January 18, 2019.

W. van Zuijlen, Minicourse on Besov spaces I  III, Junior Trimester Program: Randomness, PDEs and Nonlinear Fluctuations, August 2  December 19, 2019, Hausdorff Research Institute for Mathematics (HIM), Bonn, September 2, 2019.

W. van Zuijlen, The parabolic Anderson model in 2 d, mass and eigenvalue asymptotics, Stochastic Analysis Seminar, University of Oxford, Mathematical Institute, UK, February 4, 2019.

W. van Zuijlen, The parabolic Anderson model in 2 d, mass and eigenvalue asymptotics, Analysis and Probability Seminar, Imperial College London, Department of Mathematics, UK, February 5, 2019.

L. Andreis, A largedeviations approach to the multiplicative coagulation process, Workshop ``Woman in Probability'', May 31  June 1, 2019, Technische Universität München, Fakulät für Mathematik, May 31, 2019.

L. Andreis, Coagulating particles and gelation phase transition: a largedeviation approach, Second Italian Meeting on Probability and Mathematical Statistics, June 17  20, 2019, Vietri sul Mare, Italy, June 19, 2019.

L. Andreis, Coagulation processes and gelation from a large deviation pointof view, Berlin Mathematical School  BGSMath Junior Meeting 2019, June 26  28, 2019, Berlin Mathematical School (BMS), June 26, 2019.

L. Andreis, Largedeviation approach to coagulation processes and gelation, Workshop on Chemical Reaction Networks, July 1  3, 2019, Politecnico di Torino, Dipartimento di Scienze Matematiche ''G. L. Lagrange``, Italy, July 2, 2019.

L. Andreis, Multiplicative coagulation process and random graphs in sparse regime: a largedeviations approach, STAR Workshop on Random Graphs 2019, April 10  12, 2019, University of Groningen, Department of Mathematics and Natural Sciences, Netherlands, April 12, 2019.

L. Andreis, Phase transitions in coagulation processes and random graphs, Workshop ``Welcome Home 2019'', December 19  20, 2019, Università di Torino, Dipartimento di Matematica ``G. Peano'', Italy, December 19, 2019.

B. Jahnel, Attractor properties for irreversible and reversible interacting particle systems, QuaidiAzam University Islamabad, Pakistan, November 19, 2019.

B. Jahnel, Continuum percolation in random environment I  IV, Workshop on Probability, Analysis and Applications (PAA), September 23  October 4, 2019, African Institute for Mathematical Sciences  Ghana (AIMS Ghana), Accra, Ghana.

B. Jahnel, Coverage and mobility in devicetodevice networks, Kein öffentlicher Vortrag (Orange), Telecom Orange Paris, France, December 12, 2019.

B. Jahnel, Dynamical GibbnonGibbs transitions for the continuum WidomRowlinson model, The 41st Conference on Stochastic Processes and their Applications 2019  SPA 2019, July 8  August 12, 2019, Northwestern University Evanston, USA, July 9, 2019.

B. Jahnel, Is the Mathern process Gibbs?, Workshop on Stochastic Modeling of Complex Systems, GWOT '19, April 8  12, 2019, Universität Mannheim, Institut für Mathematik, April 9, 2019.

B. Jahnel, Three models for data propagation in mobile adhoc networks, kein öffentlicher Vortrag (Orange), Telecom Orange Paris, France, December 12, 2019.

W. König, A large deviations approach to coagulation, Maxwell Analysis Seminar, Harriot Watt University, The Maxwell Institute for Mathematical Sciences, Edinburgh, UK, December 27, 2019.

W. König, A largedeviations approach to coagulation, Workshop on Stochastic Modeling of Complex Systems, GWOT '19, April 8  12, 2019, Universität Mannheim, Institut für Mathematik, April 10, 2019.

W. König, A largedeviations approach to the multiplicative coalescent, Math Probability Seminar Series, New York University Shanghai, Institute of Mathematical Sciences, China, February 19, 2019.

W. König, A largedeviations approach to the multiplicative coalescent, 18. ErlangerMünchner Tag der Stochastik / Probability Day 2019, FriedrichAlexanderUniversität ErlangenNürnberg, Department Mathematik, May 10, 2019.

W. König, A largedeviations approach to the multiplicative coalescent, Oberseminar Wahrscheinlichkeitstheorie, Universität München, Mathematisches Institut, November 25, 2019.

W. König, Cluster size distribution in a classical manybody system, Deutsches Zentrum für Luft und Raumfahrt (DLR), Institut für Materialphysik im Weltraum, Köln, June 18, 2019.

W. König, EF4: Particles and Agents, MATH+ Day, December 13, 2019.

W. König, EF4: Particles and Agents, MATH+ Day, URANIA, December 13, 2019.

W. König, Eigenvalue order statistics and mass concentration in the parabolic Anderson model, BerlinLeipzig workshop in analysis and stochastics, January 16  18, 2019, Max Planck Institute ür Mathematik in den Naturwissenschaften, Leipzig, January 17, 2019.

W. König, Eigenvalue order statistics and mass concentration in the parabolic Anderson model, Workshop on Spectral Properties of Disordered Systems, January 7  11, 2019, Paris, France, January 11, 2019.

W. König, Eigenvalue order statistics and mass concentration in the parabolic Anderson model, Workshop on Dynamics, random media and universality of complex physical systems, August 26  30, 2019, Westfälische WilhelmsUniversität Münster, Department of Mathematics and Computer Science, August 27, 2019.

W. König, Micromacro phase transitions in coagulating particle systems IIV, Workshop on Probability, Analysis and Applications (PAA), September 23  October 4, 2019, African Institute for Mathematical Sciences  Ghana (AIMS Ghana), Accra, Ghana.

R.I.A. Patterson, Interaction clusters for the Kac process, BerlinLeipzig workshop in analysis and stochastics, January 16  18, 2019, Max Planck Institute ür Mathematik in den Naturwissenschaften, Leipzig, January 18, 2019.

R.I.A. Patterson, A novel simulation method for stochastic particle systems, Seminar Department of Chemical Engineering and Biotechnology, University of Cambridge, Faculty of Mathematics, UK, May 9, 2019.

R.I.A. Patterson, Fluctuations and confidence intervals for stochastic particle simulations, First Berlin  Leipzig Workshop on Fluctuating Hydrodynamics, August 26  30, 2019, Max Planck Institute for Mathematics in the Sciences, Leipzig, August 29, 2019.

R.I.A. Patterson, Flux large deviations, Workshop on Chemical Reaction Networks, July 1  3, 2019, Politecnico di Torino, Dipartimento di Scienze Matematiche ''G. L. Lagrange``, Italy, July 2, 2019.

R.I.A. Patterson, Flux large deviations, Seminar Statistical Laboratory, University of Cambridge, Faculty of Mathematics, UK, May 7, 2019.

R.I.A. Patterson, Interaction clusters for the Kac process, Workshopon Effective equations: frontiers in classical and quantum systems, June 24  28, 2019, Hausdorff Research Institute for Mathematics, Bonn, June 28, 2019.

R.I.A. Patterson, The role of fluctuating hydrodynamics in the CRC 1114, CRC 1114 School 2019: Fluctuating Hydrodynamics, Zuse Institute Berlin (ZIB), October 28, 2019.

R.I.A. Patterson, Kinetic interaction clusters, Oberseminar, MartinLutherUniversität HalleWittenberg, Naturwissenschaftliche Fakultät II  Chemie, Physik und Mathematik, April 17, 2019.

L. Taggi, Absorbingstate phase transition in activated random walk and oil and water, Colloquium, Università degli Studi ``La Sapienza'' di Roma, Italy, September 27, 2019.

L. Taggi, Critical density in activated random walks, Horowitz Seminar on Probability, Ergodic Theory and Dynamical Systems, Tel Aviv University, School of Mathematical Sciences, Israel, May 20, 2019.

L. Taggi, Essential enhancements for activated random walks, Second Italian Meeting on Probability and Mathematical Statistics, June 17  20, 2019, Vietri sul Mare, Italy, June 19, 2019.

L. Taggi, Nondecay of correlations in the dimer model and phase transition in lattice permutations in Z d , d > 2, via reflection positivity, Meeting of the Swiss Mathematical Society: Recent advances in loop models and height functions, September 2  4, 2019, Université Fribourg, Switzerland, September 3, 2019.

L. Taggi, Phase transition in lattice permutations and uniformly positive correlations in the dimer model in Zd, d > 2, via reflection positivity, Kolloquium des Fachbereichs Mathematik, Technische Universität Darmstadt, Fachbereich Mathematik, December 5, 2019.

L. Taggi, Uniformly positive correlations in the dimer model and phase transition in lattice permutations in Z^d, d > 2, via reflection positivity, Seminaire Probabilités et statistiques, Université Claude Bernard Lyon 1, Institut Camille Jordan (ICJ), France, November 14, 2019.
External Preprints

E. Candellero, A. Stauffer, L. Taggi, Abelian oil and water dynamics does not have an absorbingstate phase transition, Preprint no. arXiv:1901.08425v1, , 2019.

V. Betz, H. Schäfer, L. Taggi, Interacting selfavoiding polygons, Preprint no. arXiv:1902.08517, , 2019.
Abstract
We consider a system of selfavoiding polygons interacting through a potential that penalizes or rewards the number of mutual touchings and we provide an exact computation of the critical curve separating a regime of long polygons from a regime of localized polygons. Moreover, we prove the existence of a subregion of the phase diagram where the selfavoiding polygons are space filling and we provide a nontrivial characterization of the regime where the polygon length admits uniformly bounded exponential moments. 
J.D.D. Deuschel, H.E. Altman , T. Orenshtein, Über die mit Benetzungsmodellen verbundene Gradientendynamik, Preprint no. arXiv: 1908.08850, Cornell University Library, arXiv.org, 2019.

D. Heydecker , R.I.A. Patterson, Kac interaction clusters: A bilinear coagulation equation and phase transition, Preprint no. arXiv:1902.07686, , 2019.
Abstract
We consider the interaction clusters for Kac's model of a gas with quadratic interaction rates, and show that they behave as coagulating particles with a bilinear coagulation kernel. In the large particle number limit the distribution of the interaction cluster sizes is shown to follow an equation of Smoluchowski type. Using a coupling to random graphs, we analyse the limiting equation, showing wellposedness, and a closed form for the time of the gelation phase transition tg when a macroscopic cluster suddenly emerges. We further prove that the second moment of the cluster size distribution diverges exactly at tg. Our methods apply immediately to coagulating particle systems with other bilinear coagulation kernels. 
B. Lees, L. Taggi, Site monotonicity and uniform positivity for interacting random walks and the spin O(N) model with arbitrary N, Preprint no. arXiv:1902.07252, , 2019.

L. Taggi, Uniformly positive correlations in the dimer model and phase transition in lattice permutations on Zd, d>2, via reflection positivity, Preprint no. arXiv:1909.06558, , 2019.
Abstract
Our first main result is that correlations between monomers in the dimer model on Zd do not decay to zero when d>2. This is the first rigorous result about correlations in the dimer model in dimensions greater than two and shows that the model behaves drastically differently than in two dimensions, in which case it is integrable and correlations are known to decay to zero algebraically. Such a result is implied by our more general, second main result, which states the occurrence of a phase transition in the model of lattice permutations, which is related to the quantum Bose gas. More precisely, we consider a selfavoiding walk interacting with lattice permutations and we prove that, in the regime of fullypacked loops, such a walk is `long' and the distance between its endpoints grows linearly with the diameter of the box. These results follow from the derivation of an Infraredultraviolet bound from a new general probabilistic settings, with coloured loops and walks interacting at sites and walks entering into the system from some `virtual' vertice
Research Groups
 Partial Differential Equations
 Laser Dynamics
 Numerical Mathematics and Scientific Computing
 Nonlinear Optimization and Inverse Problems
 Interacting Random Systems
 Stochastic Algorithms and Nonparametric Statistics
 Thermodynamic Modeling and Analysis of Phase Transitions
 Nonsmooth Variational Problems and Operator Equations