Structure Formation and Backreaction in Growing Neutrino Quintessence
  A dependence of the neutrino masses on the dark energy scalar field could
provide a solution to the why now problem of dark energy. The dynamics of the
resulting cosmological model, growing neutrino quintessence, include an
attractive force between neutrinos substantially stronger than gravity. We
present a comprehensive approach towards an understanding of the full
cosmological evolution including the formation of large-scale neutrino
structures. Important effects we account for are local variations in the dark
energy and the backreaction on the background evolution, as well as
relativistic neutrino velocities. For this aim, we develop a relativistic
N-body treatment of the neutrinos combined with an explicit computation of the
local quintessence field. At its current stage, the simulation method is
successful until z ~ 1 and reveals a rich phenomenology. We obtain a detailed
picture of the formation of large-scale neutrino structures and their influence
on the evolution of matter, dark energy, and the late-time expansion of the
universe.
