Comparison of delensing methodologies and assessment of the delensing
  capabilities of future experiments
  Most of the CMB experiments proposed for the next generation aim to detect
the Primordial Gravitational Wave Background (PGWB). The fulfillment of this
objective depends on our capacity to separate Galactic foreground emissions and
to \emph{delens} the secondary B-mode component induced by weak gravitational
lensing. Focusing on the latter of these efforts, in this work we briefly
review the basic aspects of lensing, and exhaustively compare the performance
of current delensing methodologies and implementations within the Born
approximation as a preparation for the analysis of the data to come in the
following years. Two of the main conclusions that can be drawn from our study
are that, for next-generation experiments, delensing efficiency will still be
limited by the quality of the data itself rather than by the limitations of
current delensing methodologies, and that template delensing within the
antilensing approximation will be the optimal (balancing accuracy and
computational cost) technique to employ. We then evaluate the delensing
capabilities of future experiments (like the Simons Observatory, the CMB
Stage-IV, or the LiteBIRD and PICO satellites) by applying that methodology
onto numerical simulations of the typical CMB and lensing potential
reconstructions that they are expected to produce, and quantify how internal
and external delensing will help them to improve their sensitivity to detect
the PGWB. We also consider the benefits that a joint analysis of their data
would provide.
