Quantum mechanics provides our most fundamental description of nature, but there is a long-standing and passionate debate among physicists about what all the math “really” means. We provide an answer based on a very simple picture: The world we experience is just one of an enormous number of essentially classical worlds, and all quantum phenomena arise from a universal force of repulsion that prevents worlds from having identical physical configurations. Probabilities arise only because of our ignorance as to which world an observer occupies. This picture is all that is needed to explain bizarre quantum effects such as particles that tunnel through solid barriers and wave behavior in double-slit experiments.

Our “many-interacting-worlds” approach hinges on the assumption that interactions between deterministically evolving worlds cause all quantum effects. Each world is simply the position of particles in three-dimensional space, and each would evolve according to Newton’s laws if there were no interworld interactions. A surprising feature of our approach is that the formulation contains nothing that corresponds to the mysterious quantum wave function, except in the formal mathematical limit in which the number of worlds becomes infinitely large. Conversely, Newtonian mechanics corresponds to the opposite limit of just one world. Thus, our approach incorporates both classical and quantum theory. We perform numerical simulations and show that our approach can reproduce interference with a double slit. As few as two interacting worlds can result in quantumlike effects, such as tunneling through a barrier.

Our approach, which provides a new mental picture of quantum effects, will be useful in planning experiments to test and exploit quantum phenomena such as entanglement. Our findings include new algorithms for simulating such phenomena and may even suggest new ways to extend standard quantum mechanics (e.g., to include gravitation). Thus, while Richard Feynman may have had a point when he said “I think I can safely say that nobody understands quantum mechanics,” there is still much to be gained by trying to do so.