Controlling higher-orbital quantum phases of ultracold atoms via coupling to optical cavities

The orbital degree of freedom plays an important role in understanding exotic phenomena of strongly correlated materials. In this work, we study strongly correlated ultracold bosonic gases coupled to a high-finesse cavity, pumped by a blue-detuned laser in the transverse direction. By controlling the reflection of the pump laser, we find that atoms can be selectively transferred to the odd-parity p-orbital band or to the even-parity d-orbital band of a two-dimensional square lattice, accompanied by pronounced cavity-photon excitations. By interacting with the cavity field, atoms self-organize to form stable higher-orbital superfluid and Mott-insulating phases with orbital-density waves, as a result of cavity-induced orbital-flip hoppings. Our study opens a route to manipulate orbital degrees of freedom in strongly correlated quantum gases via coupling to optical cavities.