Wochenübersicht – letzte Woche

Wochenübersicht für die Woche vom

06 Okt 2019 bis 12 Okt 2019 (KW 42)

KW41 - KW42 - KW43 - KW44

Dienstag, 08.10 2019

Institutsseminar Kern- und Hadronenphysik

Institut für Kernphysik

Sonderseminar: 14 Uhr c.t., HS Kernphysik, Becherweg 45

Garth Huber, University of Regina, Regina, Saskatchewan, Canada
see attached pdf

Sonderseminar

Donnerstag, 10.10 2019

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ S. Jabbari / A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

10:30 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9

Christoph Ortner, University of Warwick
Accurate molecular simulation requires computationally expensive quantum chemistry models that makes simulating complex material phenomena or large molecules intractable. The past decade has seen a revival of interatomic potentials (IPs), fast but traditionally inaccurate surrogate models, re-casting their construction as an approximation and data-fitting problem. I will give an introduction to this problem, from a mixed modelling / data / mathematics perspective. In particular I want to show how it can be formalised as a high-dimensional approximation problem, with many structures that can be exploited to make it tractable. I will introduce two approximation schemes, both using different symmetric polynomials, targeting in particular efficiency and transferability, some preliminary simulation results, and the beginnings of a rigorous numerical analysis. Joint work with Geneviève Dusson (CNRS Besançon), Markus Bachmayr (Mainz), Gabor Csanyi and Cas van der Oord (Cambridge), Simon Etter (NU Singapur).

Seminar über Theorie der kondensierten Materie / TRR146 Seminar

K. Binder/ S. Jabbari / A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau

11:15 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9

Genevive Dusson, University of Warwick
I will present the practical construction of interatomic potentials for materials and molecules based on a body-order expansion (ANOVA, HDRM), each body order being represented by polynomials satisfying the rotation and permutation symmetry of the "exact" potential energy surface. These polynomials are determined in a data-driven fashion from linear fits trained with ab initio data. I will report convergence tests on training sets for materials and molecules, illustrating the accuracy, the low computational cost, and the systematic improvability of the potential. I will then outline a range of the regularisation procedures that we incorporate into the polynomial fits to achieve transferability of the potentials. Finally, I will outline a testing framework to stress-test the generalisation capabilities of new potentials far from the training set. Joint work with Alice Allen (Cambridge), Gbor Csnyi (Cambridge), Christoph Ortner (Warwick), and Cas van der Oord (Cambridge).