So quantum particles can tunnel through barriers: well, why not? The feat is not possible within a classical picture, but it’s imaginable if we don’t worry too much about how it was achieved. This doesn’t mean, however, that we should picture the electron wriggling its way through the barrier. We can predict, using the Schrödinger equation, what we will measure in a tunnelling process, but we can’t relate that to an underlying picture of an electron ‘doing’ anything. It’s better to see this effect as a manifestation of the randomness that sits at the core of quantum mechanics. The wavefunction
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