Bee has a short post on the triple-slit interference experiment: Testing the foundations of quantum mechanics. Contrary to the prediction of the writers at Nature, she does not appear to be “flummoxed” by QM.

If you know one thing about quantum mechanics, it’s Born’s rule: The probability of a measurement is the square of the amplitudes of the wave-functions. It is the central axiom of quantum mechanics and what makes it quantum. If you have a superposition of states, the amplitudes are sums of these states. Taking the square to obtain the probability means you will not only get the square of each single amplitude – which would be the classical result – but you will get mixed terms. These mixed terms are what is responsible for the interference in the famous double-slit experiment and yield the well-known spectrum with multiple maxima rather than one reproducing the two slits, as you’d get were the particles classical.