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SS22 – Abstract
Jann Zosso
(ETH Zürich)
7.7.2022
Cosmological tensions guiding the path beyond LCDM - Late time solutions to H_0 and sigma_8
Cosmology is one of the most promising testing grounds for fundamental physics and in recent years the growing evidence for the mismatch between the value of the Hubble constant H_0 inferred from the CMB and the value measured by local measurements could indeed seriously require a departure from the GR based LCDM cosmological standard model. While an abounding amount of models have already been proposed to address this so called H_0-tension, many of these alternatives are not viable at a closer look and in particular alleviate the H_0-tension only at the cost of increasing the tension with the clustering amplitude sigma_8. After a pedagogically introducing the H_0 and sigma_8 tensions, I will present in this talk recent work in which we derive generic analytical conditions any late-time modification to the LCDM expansion history must satisfy in order to simultaneously solve both these tensions. Our model independent approach therefore provides necessary requirements which can be viewed as preliminary guiding principles towards a consistent extension of the cosmological standard model.
