wavefunction doesn’t vanish completelyon the other side! There is a small probability for the
nitrogen atom to tunnel through the potential on the other side, which grows with time because the
time developments of the symmetric (e
iE 0 t
~ ) and antisymmetric (eiE 1 t
~ ) wavefunctions are different.
This fact leads to the so called Rabi oscillations: In this example the probability that the nitrogen
atom is on one side oscillates.
Rabi oscillations appear like damped harmonic oscillations. The decay of the Rabi oscillations is
called thedecoherence time. The decay appears because the system is also interacting with it’s
surrounding - other degrees of freedom.