Rescuing Palindromic Universes with Improved Recombination Modelling
  We explore the linearly quantised primordial power spectra associated with
palindromic universes. Extending the results of Lasenby et al. [1] and Bartlett
et al. [2], we improve the modelling of recombination and include higher orders
in the photonic Boltzmann hierarchy. In so doing, we find that the predicted
power spectra become largely consistent with observational data. The improved
recombination modelling involves developing further techniques for dealing with
the future conformal boundary, by integrating the associated perturbation
equations both forwards and backwards in conformal time. The resulting
wavevector quantisation gives a lowest allowed wavenumber ${k_0 = 9.93 \times
10^{-5} \textrm{Mpc}^{-1}}$ and linear spacing ${\Delta k = 1.63 \times 10^{-4}
\textrm{Mpc}^{-1}}$, providing fits consistent with observational data
equivalent in quality to the $\Lambda$CDM model.
