# Our mission

We are an international collaboration of researchers interested in developing and applying cutting-edge statistical inference techniques to study the spatial distribution of matter in our Universe. We embrace the latest innovations in information theory and artificial intelligence to optimally extract physical information from data and use derived results to facilitate new discoveries.

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# Our latest results

## Neural physical engines for inferring the halo mass distribution function

The tracing of the dark matter distribution by halos is complex and requires the knowledge of unknown small scale astrophysics. We use physically motivated neural networks to agnostically probe this bias model. The tunable parameters of the neural network are inferred as part of the BORG algorithm, and provide an exceptional fit to the halo mass distribution function. No training data is necessary since the network is conditioned on the observed halo catalogue directly.

## A fifth-force resolution of the Hubble tension

The tension between low and high redshift probes of $H_0$ is possibly the most pressing problem in cosmology today. We explore a novel resolution involving screened fifth forces, which breaks the assumption that gravity behaves identically across rungs of the cosmic distance ladder. Including existing constraints on our models, we are able to reduce the $H_0$ tension from 4.4$\sigma$ to 1.5$\sigma$.

## Algorithms for likelihood-free cosmological data analysis

Many numerical models in cosmology can only be simulated forward. We have developed two novel algorithms to perform rigorous statistical inference from these models, in two different scenarios. The first one, BOLFI, reduces the number of required simulations for physical parameter inference by several orders of magnitude. The second one, SELFI, allows a full reconstruction of the primordial matter power spectrum.

# Funding partners

We currently receive individual funding provided by the French ANR (BIG4 ANR-16-CE23-0002), the ERC, the Institut Lagrange de Paris (ANR-10-LABX-63, ANR-11-IDEX-0004-02), the CNRS, the Max Planck Institute for Astrophysics, and Imperial College London. Super computing time is provided in France by the CINES (allocation A0020410153, A0040410153).