Properties of Eigenfunctions in the Quantum Cantori Regime

We study experimentally and numerically properties of quarter-stadium billiard's eigenfunctions in the regime of quantum cantori. A quarter-stadium billiard w as simulated experimentally by a thin quarter-stadium microwave cavity. Experimental eigenfunctions in the cantori regime N = 7 - 63 of the quarter-stadium microwave billiard with the parameter ε = 0.1 were reconstructed using a field perturbation technique and a circular wave expansion method. The eigenfunctions N = 76 - 499 lying in the cantori regime of the quarter-stadium billiard with ε = 0.05 were investigated numerically. (author)