Precision cosmology with voids: definition, methods, dynamics
  We propose a new definition of cosmic voids based on methods of Lagrangian
orbit reconstruction as well as an algorithm to find them in actual data called
DIVA. Our technique is intended to yield results which can be modeled
sufficiently accurately to create a new probe of precision cosmology. We then
develop an analytical model of the ellipticity of voids found by our method
based on Zel'dovich approximation. We measure in N-body simulation that this
model is precise at the 0.1% level for the mean ellipticity of voids of size
greater than ~4 Mpc/h. We estimate that at this scale, we are able to predict
the ellipticity with an accuracy of 0.02. Finally, we compare the distribution
of void shapes in N-body simulation for two different equations of state w of
the dark energy. We conclude that our method is far more accurate than Eulerian
methods and is therefore promising as a precision probe of dark energy
phenomenology.
