Probing dark matter and the expansion history of the Universe with Lyman-alpha in absorption.

The Lyman-alpha forest in QSO absorption spectra is a sensitive probe of the matter distribution. I will present constraints on the mass of  (warm) dark matter particles   as well as active neutrinos. I will also discuss prospects of  measuring the redshift drift and improving constraints on the variability of fundamental constants with the ultra-stable high-resolution spectrograph CODEX proposed for the E-ELT.