Chisari, Nora ElisaDvorkin, CoraSchmidt, Fabian2020-05-282014Chisari, Nora Elisa, Cora Dvorkin, and Fabian Schmidt. 2014. Can Weak Lensing Surveys Confirm BICEP2? Physical Rev. D 90, no. 4 (August): 043527.1550-7998http://nrs.harvard.edu/urn-3:HUL.InstRepos:42668794The detection of B-modes in the cosmic microwave background (CMB) polarization by the BICEP2 experiment, if interpreted as evidence for a primordial gravitational wave background, has enormous ramifications for cosmology and physics. It is crucial to test this hypothesis with independent measurements. A gravitational wave background leads to B-modes in galaxy shape correlations (shear) both through lensing and tidal alignment effects. Since the systematics and foregrounds of galaxy shapes and CMB polarization are entirely different, a detection of a cross correlation between the two observables would provide conclusive proof for the existence of a primordial gravitational wave background. We find that upcoming weak lensing surveys will be able to detect the cross correlation between B-modes of the CMB and galaxy shapes. However, this detection is not sufficient to confirm or falsify the hypothesis of a primordial origin for CMB B-mode polarization.en-UScorrelationcosmological modelBICEPlensgalaxyeffect: alignmentcosmic background radiation: polarizationgravitational radiation: primordialcosmic background radiation: B-modegravitational radiation: backgroundJournal Article2020-05-2810.1103/PhysRevD.90.043527