Sum-over-paths

From Wikipedia, the free encyclopedia

Sum-over-paths, also known as Feynman sum-over-paths, is an approach to visualizing particle movement mathematically described by the equations of quantum mechanics. A competing model (though numerically identical) to the concept of probability waves, physicist Richard Feynman (who first articulated this idea) contended that fast moving subatomic particles traveled from point A to point B not by a single path, but by all possible paths.

By taking the sums of all possible paths, one reaches the same conclusions one would if associating probability waves with each traveling particle--that is, one finds the exact probabilities of eventual outcomes predicted by other theories and experimental results.

The sum-over-paths approach has become an especially useful analogy for visualizing some of the strange happenings in the frequently-counter-intuitive subatomic world. This approach is often used to explain in words the seemingly bizarre conclusions derived by mathematics and experimental results, in particular relating to the famous double slit experiment, which was a starting point of humanity's investigation into quantum mechanics (and is often a starting point of physics students' own educations in the field).