Primordial Gravity Waves and Weak Lensing

Inflation produces a primordial spectrum of gravity waves in addition to the density perturbations which seed structure formation. We compute the signature of these gravity waves in the large scale shear field. The shear can be divided into a gradient mode ([Formula presented] or [Formula presented]) and a curl mode ([Formula presented] or [Formula presented]). The latter is produced only by gravity waves, so the observations of a nonzero curl mode could be seen as evidence for inflation. We find that the expected signal from inflation is small, peaking on the largest scales at [Formula presented] at [Formula presented] and falling rapidly thereafter. Even for an all-sky deep survey, this signal would be below noise at all multipoles.