Relativistic N-Body Simulations of Horndeski Theories


IFPU
10-14 November 2025


In this program, we plan to significantly advance our project to embed Horndeski scalar-tensor theories,
formulated within the Effective Field Theory of dark energy, into the relativistic N-body program gevolution, through the opportunity to work together for a week in the same place. Combining gevolution’s N-body framework with hi class, we will model the linear and non-linear dynamics of these theories across a wide range of cosmological scales, improving predictions with essential higher-order terms of the EFT formalism. Expected outcomes include developing a robust code that captures the effects of Horndeski theories in non-linear regimes, as well as gaining novel insights into the non-linear instabilities that can arise in these dark energy models and have been observed in k-essence theories.

Organisers:

  • Martin Kuntz
  • Emilio Bellini

Participants:

  • Farbod Hassani (University of Oslo)
  • Ahmadreza Nourizonoz (University of Geneva)
  • Julian Adamek (University of Zurich)
  • Martin Kunz (University of Geneva)