Electron Scattering Through a Quantum Dot: A Phase Lapse Mechanism
  The scattering phase shift of an electron transferred through a quantum dot is studied within a model Hamiltonian, accounting for both the electron--electron interaction in the dot and a finite temperature. It is shown that, unlike in an independent electron picture, this phase may exhibit a phase lapse of $ \pi $ {\em between } consecutive resonances under generic circumstances. 
Yuval Oreg and Yuval Gefen