Instead, each path contributes what we call a probability amplitude to the entire A-B journey. Schrodinger's wave function and Feynman's path integral describe this probability amplitude thing.

A probability is always positive (or zero) and real, but an amplitude can be positive, negative, or even complex (if you don't know what a complex number is, don't worry). This changes everything.

These waves have all the same properties of water waves, but the amplitude, or height of the wave, is a probability amplitude. This amplitude can be negative, which probably seems a little strange.

Quantum mechanics says not merely that the world is probabilistic, but that it uses rules of probability that no science fiction writer would have had the imagination to invent. These rules ...

Such an interpretation treats the wave function merely as a complex probability amplitude used to calculate the probability of finding the quantum object at a given place.

Probability amplitude proportion of the excited corner states (IMAGE) Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, CAS ...