- TL;DR Summary
- How a particle behave when passing through a potential step when its energy is less than the potential itself
We know that thanks to the tunnel effect, in the case of a finite potential step (V) and considering a stationary state, when a plane wave with energy E < V encounter the step the probabability that the wave-particle coming from -∞ (where potential is V=0) will be ≠ 0, in particular the wave function will be exponential decay. We can also calculate the probability flux (J) through the potential step and the result is J=0. In my book i read that taking into account all these results, the interpretation that we can give is that considering many particles, a certain percentage will cross the step and after a definite amount of time it will turns back before setting out in the direction where it came from, this vision allow us to justify why J=0. Here is my question: once (and if) the wave-particle cross the potential step, shouldn't continue its path without turning back? There is a cause that force it to reverse the direction and that can be explain from an "intuitive" point of view?