Nonlinear reconstruction of redshift space distortions
  We apply nonlinear reconstruction to the dark matter density field in
redshift space and solve for the nonlinear mapping from the initial Lagrangian
position to the final redshift space position. The reconstructed anisotropic
field inferred from the nonlinear displacement correlates with the linear
initial conditions to much smaller scales than the redshift space density
field. The number of linear modes in the density field is improved by a factor
of 30-40 after reconstruction. We thus expect this reconstruction approach to
substantially expand the cosmological information including baryon acoustic
oscillations and redshift space distortions for dense low-redshift large scale
structure surveys including for example SDSS main sample, DESI BGS, and 21 cm
intensity mapping surveys.
