Controlling van der Waals Phenomena at the interface of Atomic and Two-Dimensional Dirac Quantum Matter*

We discuss how the presence of two-dimensional (2D) materials, such as graphene, can significantly affect two intrinsically quantum phenomena that have traditionally served as probes of the fundamental van der Waals (VDW) interaction. First, we show theoretically that Quantum Reflection (QR) of slow atoms off attractive VDW potential tails (due to interactions with 2D materials) is very strongly dependent on material characteristics (such as band structure, doping and screening level, etc). Secondly, we analyze manifestations of such 2D effects for many atoms forming a confined Bose-Einstein condensate (BEC) placed near 2D materials, which in turn makes the BEC frequency sensitive to the interface. In both cases we find that relatively small 2D material changes (either by external factors such as strain or doping, or by using gapped 2D materials instead of graphene) can have a profound effect on the above phenomena. In particular, Quantum Reflection at a given energy can experience a significant enhancement or supression (relative to conventionally used bulk materials) making 2D quantum materials an attractive playground for the study of many-body phenomena at the interface of atomic and solid state physics.