Structure Formation in the Symmetron Model
  Scalar fields, strongly coupled to matter, can be present in nature and still
be invisible to local experiments if they are subject to a screening mechanism.
The symmetron is one such mechanism which relies on restoration of a
spontaneously broken symmetry in regions of high density to shield the scalar
fifth force. We have investigated structure formation in the symmetron model by
using N-body simulations and find strong observable signatures in both the
linear and nonlinear matter power spectrum and on the halo mass function. The
mechanism for suppressing the scalar fifth force in high density regions is
also found to work very well.
