Improved cosmological fits with quantized primordial power spectra

Download paper here

Abstract

We observationally examine cosmological models based on primordial power spectra with quantized wave vectors. Introducing a linearly quantized power spectrum with $k_0=3.225\times10^{-4}\mathrm{Mpc}^{-1}$ and spacing $\Delta k = 2.257 \times 10^{-4} \mathrm{Mpc}^{-1}$ provides a better fit to the Planck 2018 observations than the concordance baseline, with $\Delta \chi^2 = -8.55$. Extending the results of Lasenby et al. 2022, we show that the requirement for perturbations to remain finite beyond the future conformal boundary in a universe containing dark matter and a cosmological constant results in a linearly quantized primordial power spectrum. It is found that the infrared cutoffs for this future conformal boundary quantized cosmology do not provide cosmic microwave background power spectra compatible with observations, but future theories may predict more observationally consistent quantized spectra.

CMB power spectrum residuals between future conformal boundary quantized cosmologies and the $\Lambda$CDM baseline. $\Lambda$CDM + FCB quantization is in red and green, while $\Lambda$R + FCB is in blue and orange. The Planck data residuals are also plotted for reference. The quantized cosmologies only allow comoving wave numbers $k$ such that perturbations remain finite for all conformal times. This restriction results in a drop in power at low $\ell$ due to a minimum allowed $k_0$ (and a corresponding rise at $k_0$) and oscillatory features from the finite spacing $\Delta k$ between allowed wave vectors. The cosmological parameters for all models are fixed to the Planck baseline value.