  This work is concerned with a simple model for a polar fluid, a Gaussian
field model based on the excess density and on the polarization. It is a
convenient framework to implement the dielectric properties of correlated
liquids that stem from nanometric correlations between molecules. It allows to
study the effects of coupling terms between density and polarization on the
structure of the fluid. Despite the simplicity of such a model, it can capture
some interesting features of the response functions of water such as the
quasi-resonant longitudinal dielectric susceptibility or the presence of two
maxima in the structure factor. Explicit models of water generate extremely
high computational cost and implicit models sometimes fail to treat properly
the electrostatic interactions. A Gaussian field theory could therefore be an
interesting alternative to describe water.
