Underbarrier interference and Euclidean resonance
  Quantum tunneling from a thin wire or a thin film through a static potential barrier in a zero magnetic field is studied. The wire or the film should satisfy a condition of transverse quantization of levels and be inhomogeneous. Depending on a form of the inhomogeneity the tunneling scenario can dramatically differ from the conventional scheme of an exponential decay of a probability density inside the barrier. This happens due to interference of various underbarrier paths, which are collected at some points giving rise to a trans-barrier state of a large amplitude. As a result, the tunneling probability through an almost classical barrier can be not exponentially small. This is a phenomenon of Euclidean resonance studied earlier for tunneling across nonstationary barriers. 
B. Ivlev