# Sisyphus cooling

Sisyphus cooling can be achieved by shining two counter-propagating laser beams with orthogonal polarization onto an atom sample. The two interfering beams create a standing wave with a polarization gradient that alternates between $\sigma^+$-, $\pi$- and $\sigma^-$-Polarisation. Atoms moving through the potential landscape along the direction of the standing wave lose kinetic energy as they move to a potential maximum, at which point optical pumping moves them to a lower-energy state, thus ridding them of the potential energy they carried.