Two-Dimensional Materials as Laboratories for Fundamental Physics

Novel two-dimensional, atomically thin materials, notably graphene and transition-metal dichalcogenides, exhibit exotic Dirac quasiparticle spectra and can serve as experimental and theoretical laboratories for understanding fundamental physical phenomena, such as the nature of the van der Waals force between atoms and material surfaces. van der Waals forces are the most common manifestations of electromagnetism in Nature and govern the interactions between neutral objects on mesoscopic scales. Yet they are very hard to “engineer” and manipulate effectively, and here the newly-discovered graphene-type materials can lead to fundamental progress. I will discuss recent progress and my results in the following main directions: (1) I will describe how van der Waals interactions between cold atoms and graphene arise and the way physicists calculate them. The atoms have to be fairly “cold” so that thermal motion and other dissipation effects do not interfere with the main phenomenon. (2) I will present recent results on how we can effectively change the strength of these interactions. In particular I will discuss how changing the number of electrons in the graphene sheet (via application of voltage) can lead to changes in the van der Waals force. Other ways of manipulating, or “quantum engineering” such forces will also be mentioned, namely effects of strain and using other atomically thin materials instead of graphene