A New Window into Stochastic Gravitational Wave Background

Understand

A stochastic gravitational wave background (SGWB) would gravitationally lens the cosmic microwave background (CMB) photons.

• We find that the lensing due to gravitational waves(GW) is more efficient as compared to lensing due to scalar density perturbations.
• Though the effect of lensing due to GW is found to effect all the four CMB power spectra, its effect is most prominently seen in the CMB polarization power spectra.
• This suggests that the measurements of the CMB angular power spectra could be used to constraining the energy density ($\Omega_{GW}$) of the SGBW.