Extracting high-order cosmological information in galaxy surveys with
  power spectra
  The reconstruction method was proposed more than a decade ago to boost the
signal of baryonic acoustic oscillations measured in galaxy redshift surveys,
which is one of key probes for dark energy. After moving observed galaxies in
galaxy surveys back to their initial position, the reconstructed density field
is closer to a linear Gaussian field, with higher-order information moved back
into the power spectrum. By combining power spectra measured from the pre- and
post-reconstructed galaxy samples, higher-order information beyond the 2-point
power spectrum can be efficiently extracted, as power spectra can be measured
more quickly than direct measurements of the bispectrum and other higher order
functions. This opens a new window to easily use higher-order information when
constraining cosmological models.
