Bachelor-/Masterseminar:

Mathematical Optimization

winter 2020/21

Lecturer:  Benedikt Wirth
 Manuel Friedrich

Information on the seminar

time, location: tba; block course possible
learnweb: SeminarFriedrichWirth-2020_2
contents: We plan to have talks about analytical and numerical topics on structures from materials science, e.g. crystallization results (that atoms arrange in crystals), atomistic-to-continuum coupling (numerics in which some regions are resolved at atomistic scale), results and simulations on dislocations and similar structures in materials, results on carbonanostructures (such as fullerenes). Techniques range from numerical analysis via the calculus of variations all the way to discrete mathematics.
prerequisites:  Analysis I-III, some knowledge in numerics/differential equations/variational calculus is helpful.
initial meeting: The first meeting takes place October 28, 2020, 14:00 via zoom.

Login data: Meeting-ID: 839 1651 5225, Kenncode: 7gThm9

In case you are interested in the seminar, please already now send an e-mail to the lecturer. If you already would like to find a topic or even start working before October, this is also possible (again just send an e-mail).
assessment: 45-minute seminar talk and written report (ca. 7-page handout, to be presented and discussed with the lecturer ca. 10 days before the talk, to allow for improvements and further assistance)
topics:  The following list of articles gives an impression of possible topics:
  1. Crystallization:

    Friesecke, De Luca: Crystallization in Two Dimensions and a Discrete Gauss–Bonnet Theorem

    Mainini, Piovano, Stefanelli: Finite Crystallization in the Square Lattice

    Schmidt: Ground states of the 2D sticky disc model: fine properties and N3/4 law for the deviation from the asymptotic Wulff shape

    Theil: A Proof of Crystallization in Two Dimensions

  2. Coupling of atomistic and continuum models:

    Braides, Solci, Vitali: A derivation of linear elastic energies from pair-interaction atomistic systems

    Blanc, Le Bris, Lions: Atomistic to continuum limits for computational materials science

    Au Yeung, Friesecke, Schmidt: Minimizing atomic configurations of short range pair potentials in two dimensions: crystallization in the Wulff shape

  3. Numerical methods for coupling of atomistic and continuum models:

    wie Textbuch: Luskin, Ortner: Atomistic-to-continuum-coupling

    Dedner, Ortner, Wu: Coupling atomistic, elasticity and boundary element models

    Ortner, Shapeev, Zhang: (In-)stability and stabilisation of qnl-type atomistic-to-continuum coupling methods

    Wang, Chen, Liao, Ortner, Wang, Zhang: A posteriori error estimates for adaptive qm/mm coupling methods

    Salvalaglio, Voigt, Elder: Closing the gap between atomic-scale lattice deformations and continuum elasticity

  4. Stability of molecules:

    Friedrich, Piovano, Stefanelli: The geometry of C60: A rigorous approach via Molecular Mechanics

    Friedrich, Mainini, Piovano, Stefanelli: Characterization of optimal carbon nanotubes under stretching and validation of the Cauchy-Born rule

    Betermin, Friedrich, Stefanelli: Angle-rigidity for Z^2 configurations
  5. Stability of crystal defects:

    Ehrlacher, Ortner, Shapeev: Analysis of boundary conditions for crystal defect atomistic simulations

    Hudson, Ortner: Analysis of stable screw dislocation configurations in an anti-plane lattice model

    Buze, Hudson, Ortner: Analysis of cell size effects in atomistic crack propagation

    Nitschke, Reuther, Voigt: Liquid crystals on deformable surfaces

  6. Parameterfitting for atomistic and quantum systems:

    van der Oord, Dusson, Csanyi, Ortner: Regularised atomic body-ordered permutation-invariant polynomials for the construction of interatomic potentials

    Bachmayr, Csanyi, Dusson, Etter, van der Oord, Ortner: Approximation of potential energy surfaces with spherical harmonics

    Onat, Ortner, Kermode: Sensitivity and dimensionality of atomic environment representations used for machine learning interatomic potentials



talks: