Stabilization of decaying states and quantum vortices
  A two-dimensional model of an electron moving under the influence of an attractive zero-range potential as well as external magnetic and electric fields is analyzed. We prove by numerical investigations that there are formed such resonances which manifest a peculiar dependance on the electric field intensity, i.e., although the electric field increases, the lifetime of these resonance states grows up. It is explained that this phenomenon, called further \textit{the stabilization}, is a close consequence of \textit{quantum-mechanical vortices} induced by the magnetic field and controlled by the electric field strength. In order to get more information about these vortices the phase of wavefunctions as well as the probability current for these stable resonances are investigated. 
Katarzyna Krajewska and Jerzy Z. Kaminski