Vlasov limit and discreteness effects in cosmological N-body simulations
arXiv:0805.1500 · doi:10.1016/j.cnsns.2007.03.026
Abstract
We present the problematic of controlling the discreteness effects in cosmological N-body simulations. We describe a perturbative treatment which gives an approximation describing the evolution under self-gravity of a lattice perturbed from its equilibrium, which allows to trace the evolution of the fully discrete distribution until the time when particles approach one another ("shell-crossing"). Perturbed lattices are typical initial conditions for cosmological N-body simulations and thus we can describe precisely the early time evolution of these simulations. A quantitative comparison with fluid Lagrangian theory permits to study discreteness effects in the linear regime of the simulations. We show finally some work in progress about quantifying discreteness effects in the non-perturbative (highly non-linear) regime of cosmological N-body simulations by evolving different discretizations of the same continuous density field.
arXiv comment8 pages, proceedings (refereed) of "Vlasovia 2006", 2nd int'l workshop on the theory and applications of the Vlasov equation, Florence, September 2006. A more detailed report on recent progress may be found at arXiv:0805.1357
References in corpus (11)
- The Inner Structure of LambdaCDM Halos I: A Numerical Convergence Study
- Approximation Methods for Non-linear Gravitational Clustering
- Two body relaxation in CDM simulations
- Fundamental Discreteness Limitations of Cosmological N-Body Clustering Simulations
- Statistical Physics for Cosmic Structures
- Demonstrating Discreteness and Collision Error in Cosmological N-body Simulations of Dark Matter Gravitational Clustering
- Linear perturbative theory of the discrete cosmological N-body problem
- Two-Body Relaxation in Cosmological Simulations
- Statistical physics for complex cosmic structures
- Gravitational evolution of a perturbed lattice and its fluid limit
- Power-law correlation and discreteness in cosmological N-body simulations