First experimental evidence for quantum echoes in scattering systems
  A self-pulsing effect termed quantum echoes has been observed in experiments with an open superconducting and a normal conducting microwave billiard whose geometry provides soft chaos, i.e. a mixed phase space portrait with a large stable island. For such systems a periodic response to an incoming pulse has been predicted. Its period has been associated to the degree of development of a horseshoe describing the topology of the classical dynamics. The experiments confirm this picture and reveal the topological information. 
C. Dembowski (1), B. Dietz (1), T. Friedrich (1), H.-D. Graef (1), A.   Heine (1), C. Mejia-Monasterio (2), M. Miski-Oglu (1...