Aharonov-Bohm caging and inverse Anderson transition in ultracold atoms

Aharonov-Bohm (AB) caging, a special flat-band localization mechanism, has spurred great interest
in different areas of physics. AB caging can be harnessed to explore the rich and exotic physics of
quantum transport in flatband systems, where geometric frustration, disorder and correlations act
in a synergetic and distinct way than in ordinary dispersive band systems. In contrast to the ordinary
Anderson localization, where disorder induces localization and prevents transport, in flat band
systems disorder can induce mobility, a phenomenon dubbed inverse Anderson transition. Here,
we report on the experimental realization of the AB cage using a synthetic lattice in the momentum
space of ultracold atoms with tailored gauge fields, demonstrate the geometric localization due
to the flat band and the inverse Anderson transition when correlated binary disorder is added to
the system. Our experimental platform in a many-body environment provides a fashiinating quantum
simulator where the interplay between engineered gauge fields, localization, and topological
properties of flat band systems can be finely explored