The benefits of CMB delensing

Abstract The effects of gravitational lensing the cosmic microwave background (CMB) have been measured at high significance with existing data and will be even more precisely in future surveys. Reversing on observed CMB temperature polarization maps provides a variety benefits. Delensed spectra sharper acoustic peaks prominent damping tails, allowing for improved inferences cosmological parameters that impact those features. Delensing reduces B -mode power, aiding search primordial waves lower variance reconstruction other sources secondary anisotropies. Lensing-induced power spectrum covariances are reduced by delensing, simplifying analyses improving constraints non-Gaussianities. Biases result from incorrectly modeling nonlinear baryonic feedback mitigated delensing. All these benefits possible without any changes to experimental or survey design. We develop self-consistent, iterative, all-orders treatment delensing curved sky demonstrate