Fig. 1.

a–d Phase diagrams for the empirical data. e–h Phase diagrams for the SK model. a, e: ∣m∣. b, f: q. c, g: χ_SG. d, h: χ_uni. In a, d the crosses represent the mean and standard deviation of the J_ij estimated for the entire population of the participants, i.e., ($\widehat{\mu }$, $\widehat{\sigma }$). In c a circle represents a participant. In a and e we plot ∣m∣ instead of m. This is because averaging over simulations and over realizations of J would lead to m ≈ 0 due to symmetry breaking, even if m ≠ 0 in theory such as in the ferromagnetic phase. i χ_SG as a function of σ, with $\mu =\widehat{\mu }$ being fixed. j χ_uni as a function of μ, with $\sigma =\widehat{\sigma }$ being fixed. In i and j, the curves are the cross-sectional view of c and d, respectively, along the dashed line in c or d. The circles in i and j represent the individual participants and are the projection of the circles in c and d onto the dashed line. k Scaling behavior of χ_SG when the system size $N^{\prime }$ is varied. The value of σ = σ_peak that maximizes χ_SG is plotted against $1∕N^{\prime }$ in the inset. The dashed line is the linear regression based on the six data points, $N^{\prime }=40,60,80,120,160$, and 264. The coefficient of determination is denoted by R².