We are interested in studying the repulsive interactions between atoms and light-atom interactions.
One of our long-term goals is to study repulsive van der Waals interactions and to create few-body molecules using van der Waals interactions. For instance, van der Waals interactions can be used to create dimers, trimmers, and stable molecules, which are not achievable through common methods. In this case, van der Waals interactions are the dipole-dipole interactions between atoms. We use an atom, one electron and one ion core, as an electric dipole, whose size depends on the distance between the electron and ion core. To increase this electric dipole, we excite the atoms to Rydberg states, or highly excited states.
All these experiments are carried out at very low temperatures (T<<1 Kelvin or T≈0.3 mK). How to cool the atoms to such low temperatures? Similar to the two-car collision as shown in Fig. 1(a), the collision between one atom and one photon, or quantized light, can change the atom’s speed according to the momentum conservation as shown in Fig. 1(b).