  We consider a system composed by N atoms trapped within a multimode cavity,
whose theoretical description is captured by a disordered multimode Dicke
model. We show that in the resonant, zero field limit the system exactly
realizes the Sherrington-Kirkpatrick model. Upon a redefinition of the
temperature, the same dynamics is realized in the dispersive, strong field
limit. This regime also gives access to spin-glass observables which can be
used to detect Replica Symmetry Breaking.
