Cosmology from the Lyman-alpha forest

The Lyman-alpha forest is a unique probe of extensions to the Standard Models of cosmology and particle physics. Being the absorption lines of hydrogen in the spectra of distant quasars, it traces the clustering of matter on a remarkable range of redshifts (from z = 2 – 6) and scales (from sub-Mpc to hundreds of Mpc). I will review how we can learn (on small scales) about massive neutrinos, dark matter candidates like axions or sterile neutrinos and the physics of inflation — and (on large scales) a determination of the cosmological expansion rate through the baryon acoustic oscillations peak. The challenge lies in disentangling the cosmology and the astrophysics of the intergalactic medium. I will discuss my work in disentangling the biasing effect of high-density hydrogen absorbers, thus helping to realise the potential of future big surveys like the Dark Energy Spectroscopic Instrument.