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Ultraviolet properties of Lifshitz-type scalar field theories

We consider Lifshitz-type scalar field theories that exhibit anisotropic scaling laws near the ultraviolet fixed point, with explicit breaking of Lorentz symmetry. It is shown that, when all momentum dependent vertex operators are discarded, actions with anisotropy parameter z=3 in 3+1 dimensions generate Lorentz symmetry violating quantum corrections that are suppressed by inverse powers of the momentum, so that the symmetry is sensibly restored in the infrared region. In the ultraviolet region, the singular behavior of the corrections is strongly smoothened: only logarithmic divergences show up, producing very small changes of the couplings over a range of momentum of many orders of magnitude. In the particular case where all couplings are equal, the theory shows a Liouville-like potential and quantum corrections are exactly summable, giving an asymptotically free theory. However, the observed weakening of the divergences is not sufficient to avoid a residual fine tuning of the mass parameter at a very high energy scale, in order to recover a physically acceptable mass in the infrared region.