%0 Journal Article %T Symmetry breaking in crossed magnetic and electric fields %A C. Neumann %A R. Ubert %A S. Freund %A E. Floethmann %A B. Sheehy %A K. H. Welge %A M. R. Haggerty %A J. B. Delos %J Physics %D 1997 %I arXiv %R 10.1103/PhysRevLett.78.4705 %X We present the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field, and we give a semiclassical interpretation of this effect. As the small perpendicular electric field is added, the recurrence strengths of closed orbits decrease smoothly to a minimum, and revive again. This phenomenon, caused by interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits. %U http://arxiv.org/abs/physics/9701014v2