Coupled Microwave Billiards as a Model for Symmetry Breaking
  Two superconducting microwave billiards have been electromagnetically coupled in a variable way. The spectrum of the entire system has been measured and the spectral statistics analyzed as a function of the coupling strength. It is shown that the results can be understood in terms of a random matrix model of quantum mechanical symmetry breaking -- as e.g. the violation of parity or isospin in nuclear physics. 
H. Alt, C. I. Barbosa, H.-D. Graef, T. Guhr, H.L. Harney, R.   Hofferbert, H. Rehfeld, and A. Richter