PIRSA:18110058

Reproducibility despite exponential divergence in the Newtonian few-body problem

Portegies Zwart, S. (2018). Reproducibility despite exponential divergence in the Newtonian few-body problem. Perimeter Institute. https://pirsa.org/18110058

Portegies Zwart, Simon. Reproducibility despite exponential divergence in the Newtonian few-body problem. Perimeter Institute, Nov. 14, 2018, https://pirsa.org/18110058 

          @misc{ pirsa_PIRSA:18110058,
            doi = {10.48660/18110058},
            url = {https://pirsa.org/18110058},
            author = {Portegies Zwart, Simon},
            keywords = {Other},
            language = {en},
            title = {Reproducibility despite exponential divergence in the Newtonian few-body problem},
            publisher = {Perimeter Institute},
            year = {2018},
            month = {nov},
            note = {PIRSA:18110058 see, \url{https://pirsa.org}}
          }

Simon Portegies Zwart Leiden University

DOI 10.48660/18110058
Collection
Talk Type Scientific Series
Subject

Abstract

Energy and momentum are conserved in Newton's laws of gravitation.
Numerical integration of the equations of motion should comply to
these requirements in order to guarantee the correctness of a
solution, but this turns out to be insufficient.  The steady growth of
numerical errors and the exponential divergence, renders numerical
solutions over more than a dynamical time-scale meaningless.  Even
time reversibility is not a guarantee for finding the definitive
solution to the numerical few-body problem.  As a consequence,
numerical N-body simulations produce questionable results.  Using
brute force integrations to arbitrary numerical precision I will
demonstrate empirically that the statistics of an ensemble of resonant
3-body interactions is independent of the precision of the numerical
integration, and conclude that, although individual solutions using
common integration methods are unreliable, an ensemble of approximate
3-body solutions accurately represent the ensemble of true solutions.