Fig. 1: Coupled order parameters.
From: Cavity-mediated charge and pair-density waves in a unitary Fermi gas
a Charge-density wave (Θ), pair-density wave (Π), and in-phase cavity-field quadrature (X) represent the three coupled orders. Λ, the strength of the dispersive atom-cavity coupling, is controlled via the pump strength V0. r denotes the relative strength of the dispersive coupling of atoms and pairs to the cavity. Θ and Π are mutually coupled by strong atom-atom interactions with a strength U. b Schematic phase boundary separating the normal (X = 0) from the superradiant phase (X ≠ 0) as a function of V0 and −1/r, showing a characteristic Fano-type profile. c Single atoms (left) and pairs of atoms (right) in a unitary Fermi gas within the mode of a high-finesse cavity can scatter photons from a transverse pump into the cavity and vice versa. The pump (red arrows) forms a standing wave with a wavevector \({\overrightarrow{k}}_{p}\). The dispersive coupling strengths Λ and rΛ are determined by the detuning Δa between the pump (p) and the atomic resonance (a), and the detuning Δm between the pump and a photo-association resonance (m), respectively.
