Figure 3. Lévy statistics of intensity emission and the RSB glassy transition.

Dependence on the excitation pulse energy of (a) the value q_max at which the Parisi overlap order parameter assumes its maximum and (b) the Lévy index α calculated from the data in Fig. 2 of the Nd:YBO system. The regime of Lévy statistics (0 < α < 2) coincides with the critical region of the RSB transition to the RL glassy behavior. The value α = 2 identifies the Gaussian regimes below and above the transition. Notice that well above the threshold the SG behavior tends to be suppressed as q_max decreases.