While this quantum phase transition between a metallic delocalized state and an insulating localized state resembles the disorder-driven Anderson localization transition, there are some key differences between the two phenomena. In particular the Aubry–André model has no actual disorder, only incommensurate modulation of onsite energies. This is why the Aubry-André transition happens at a finite value of the pseudo-disorder strength λ λ , whereas in one dimension the Anderson transition happens at zero disorder strength.