Upcoming Events
- Tuesday, 17.09.2024, 10:15 (WIAS-406)
- Seminar Nichtlineare Optimierung und Inverse Probleme
Prof. Dr. Masahiro Yamamoto, University of Tokyo, Japan:
Inverse problems for time-fractional diffusion-wave equations
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Host
WIAS Berlin
- Wednesday, 18.09.2024, 10:00 (WIAS-405-406)
- Seminar Numerische Mathematik
Albert J. Pool, Deutsches Zentrum für Luft- und Raumfahrt e.V.:
Nonlinear dynamics as a ground-state solution on quantum computers
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstract
For the solution of time-dependent nonlinear differential equations, we present variational quantum algorithms (VQAs) that encode both space and time in qubit registers. The spacetime encoding enables us to obtain the entire time evolution from a single ground-state computation. We describe a general procedure to construct efficient quantum circuits for the cost function evaluation required by VQAs. To mitigate the barren plateau problem during the optimization, we propose an adaptive multigrid strategy. The approach is illustrated for the nonlinear Burgers equation. We classically optimize quantum circuits to represent the desired ground-state solutions, run them on IBM Q System One and Quantinuum System Model H1, and demonstrate that current quantum computers are capable of accurately reproducing the exact results.
Host
WIAS Berlin
- Tuesday, 24.09.2024, 10:15 (WIAS-406)
- Seminar Nichtlineare Optimierung und Inverse Probleme
Bernhard Höveler, Technische Universität Berlin, Institut für Mathematik:
An analogue for the Gramian of a linear quadratic regulator for nonlinear control systems and its approximability by finite rank operators
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Host
WIAS Berlin
- Wednesday, 09.10.2024, 11:30 (WIAS-405-406)
- Seminar Interacting Random Systems
Christopher Renaud Chan, Université Grenoble Alpes:
tba
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Further Informations
Seminar Interacting Random Systems (Hybrid Event)
Host
WIAS Berlin
- Wednesday, 30.10.2024, 10:00 (WIAS-405-406)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Prof. Dr. Tomáš Roubíček, Czech Academy of Sciences, Tschechische Republik:
Time discretization in visco-elastodynamics at large displacements and strains in the Eulerian frame
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstract
The fully-implicit time discretization (i.e. the backward Euler formula) is applied to compressible nonlinear dynamical models of viscoelastic media in the Eulerian description, i.e. in the actual deforming configuration. The Kelvin--Voigt rheology or also, in the deviatoric part, the Jeffreys (also called anti-Zener) rheology describing a (possibly nonlinear) creep or a rate-dependent plasticity are considered. Both a linearized convective model at large displacements with a convex stored energy and the fully nonlinear large strain variant with a (possibly generalized) polyconvex stored energy are considered. The time-discrete suitably regularized schemes (suggesting an implementable numerical strategy) are devised for both these heavily nonlinear cases. The numerical stability and, considering the multipolar 2nd-grade viscosity, also convergence towards weak solutions are proved, exploiting the convexity of the kinetic energy when written in terms of linear momentum instead of velocity. In the fully nonlinear case, the examples of neo-Hookean and Mooney--Rivlin materials are presented. A comparison with models of viscoelastic barotropic fluids is also made and thermodynamical extension is outlined, too.
Further Informations
Oberseminar “Nichtlineare Partielle Differentialgleichungen” (Langenbach Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin