Cosmic expansion history from SNe Ia data via information field theory -- the charm code

Understand

We present charm (cosmic history agnostic reconstruction method), a novel inference algorithm that reconstructs the cosmic expansion history as encoded in the Hubble parameter $H(z)$ from SNe Ia data.

• The novelty of the approach lies in the usage of information field theory, a statistical field theory that is very well suited for the construction of optimal signal recovery algorithms.
• The charm algorithm infers non-parametrically $s(a)=\ln(\rho(a)/\rho_{\mathrm{crit}0})$, the density evolution which determines $H(z)$, without assuming an analytical form of $\rho(a)$ but only its smoothness with the scale factor $a=(1+z)^{-1}$.
• The inference problem of recovering the signal $s(a)$ from the data is formulated in a fully Bayesian way.