  We present a simple model in which the weak energy condition is violated for
spatially homogeneous, slowly evolving fields. The excitations about
Lorentz-violating background in Minkowski space do not contain ghosts, tachyons
or superluminal modes at spatial momenta ranging from some low scale epsilon to
the UV cutoff scale, while tachyons and possibly ghosts do exist at p^2 <
epsilon^2. We show that in the absence of other matter, slow roll cosmological
regime is possible; in this regime p+rho<0, and yet homogeneity and isotropy
are not completely spoiled (at the expence of fine-tuning), since for given
conformal momentum, the tachyon mode grows for short enough period of time.

High Energy Physics - Theory