Coherent control of Anderson localization in phase-modulated quasiperiodic lattices

We report recent experiments on the coherent control of Anderson localization by phason modulation in a quasiperiodic system. Despite the fact that the phason degree of freedom in the static 1D Aubry-André model doesn't affect the localization transition, we show both theoretically and experimentally that this localization transition can be controlled and destroyed completely by periodic phason modulation, without changing the pseudo-disorder strength. By experimentally observing the in-situ expansion of a BEC in a phase-modulated bichromatic lattice, we map out the rescaling of the effective disorder and observe the destruction of localization, demonstrate its use as a knob for coherent control of localization, and explore a possible protocol for reversing the apparent arrow of time. We elucidate connections between these phenomena and higher-dimensional dynamical localization in integer quantum Hall systems.