  We study correlations amongst tidal fields originated by the large-scale
distribution of matter in the Universe. The two-point tidal correlation is
described as a rank-4 tensor, whose elements can be written in terms of four
fundamental scalar functions ranging, with respect the spatial separation, from
purely transversal to purely longitudinal correlations. Tidal fields, both on
galaxy and cluster scales, reveal to be correlated over distances larger than
the mass-density correlation lenght, though traceless tidal fields show
anti-correlation between diagonal terms along orthogonal directions. The
cross-correlation between mass and tidal field is also analyzed. These results
are relevant for galaxy formation and the interpretation of large-scale weak
lensing phenomena.
