Experimental investigation of the fluctuations in nonchaotic scattering in microwave billiards

Zhang Runzu^{1, 2}, Zhang Weihua^{1, 2}, Dietz Barbara^{1, 2, †}, Chai Guozhi², Huang Liang^{1, 2}

Fluctuation properties of the unfolded eigenfrequencies of the empty microwave billiard: (a) the nearest neighbor spacing distribution P(s), (b) the cumulative nearest-neighbor spacing distribution I(s), (c) the number variance Σ 2 ( L ) , and (d) the Dyson–Mehta statistics Δ 3 ( L ) . The solid, dashed, and dash-dotted black lines show the curves for Poisson, GOE, and semi-Poisson statistics, respectively. The red histograms and diamonds show the curves deduced from the measurements, the green histograms and solid lines were obtained from the computed eigenvalues; see Eq. (3).