Optical fields to control ultracold atomic molecular collisions

Research focusing on the formation of ultracold atomic and molecular quantum gases is a continuously expanding field due to its envisioned applications such as quantum-controlled chemistry or quantum simulation. The aim of our theoretical work is to find ways to suppress inelastic or reactive processes between colliding particles in ultracold quantum gases. Using a laser field detuned to the blue of a relevant transition, we propose to couple the initial colliding particle state to a repulsive excited one, thus preventing the particles to come close to each other. This ``blueshielding'' technique is applied for ultracold quantum gases, close to quantum degeneracy. Due to the extremely small collisional energies it is possible to address a single repulsive channel thus ensuring a full control of the suppression efficiency. We will present our results in case of the39K133Cs molecule. $[1]$ A. Orban.et al. Phys. Rev. A, \textbf92, 265 (2015). $[2]$ A. Orban.et al. Phys. Rev. A,\textbf{92}, 265 (2015).