The End of Ab Initio MD

  • TH Department Online Seminar
  • Date: Jun 30, 2022
  • Time: 11:00 AM
  • Speaker: Prof. Gábor Csányi
  • University of Cambridge, Department of Engineering, Cambridge, United Kingdom
  • Location: https://zoom.us/j/91272966563?pwd=eGo0V2Mrd3pwOXVaVXJ0VklGd041QT09
  • Room: Meeting ID: 912 7296 6563 | Passcode: 057467
  • Host: TH Department
The End of <i>Ab Initio</i> MD
A new computational task has been defined and solved over the past 15 years for extended material systems: the analytic fitting of the Born-Oppenheimer potential energy surface as a function of nuclear coordinates under the assumption of medium-range interactions, 5 ~ 10 Å.

The resulting potentials are reactive, many-body, reach accuracies of a few meV/atom, with evaluation costs that are on the order of 1-10 ms/atom/cpucore. Applications to diverse material systems are being published every week, and the extension to molecular force fields is well underway. Important challenges remain: treatment of long range interactions in the form of charge self-consistency, magnetism etc. On the methodological side, with deeper understanding of the geometry problem of describing environments comes what appears to be a convergence between various modeling approaches (neural networks, kernels, polynomials). Protocols of putting together the training data are being explored, including "active learning". I am particularly interested in the amount physics and chemistry "knowledge" that we can impute into these approximations, and that they can be used to help "extrapolate" correctly into regions of configuration space far from those in the data set.

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