How smooth are particle trajectories in a ΛCDM Universe

@article{Rampf2015HowSA,
  title={How smooth are particle trajectories in a $\Lambda$CDM Universe},
  author={Cornelius Rampf and Barbara Villone and Uriel Frisch},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2015},
  volume={452},
  pages={1421-1436}
}
It is shown here that in a flat, cold dark matter (CDM) dominated Universe with positive cosmological constant ($\Lambda$), modelled in terms of a Newtonian and collisionless fluid, particle trajectories are analytical in time (representable by a convergent Taylor series) until at least a finite time after decoupling. The time variable used for this statement is the cosmic scale factor, i.e., the "$a$-time", and not the cosmic time. For this, a Lagrangian-coordinates formulation of the Euler… 

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