Parallel universes really exist and interact, says a team of scientists from the University of California Davis and Griffith University in Brisbane, Australia. “Such an interaction could explain everything that is bizarre about quantum mechanics.”

Quantum mechanics is needed to explain how our Universe works at the microscopic scale, and is believed to apply to all matter.

But there is a long-standing and passionate debate among physicists about what all the math really means.

The ‘Many Interacting Worlds’ approach proposed by the team, led by Prof Howard Wiseman of Griffith University, provides a new perspective on this baffling field.

“The idea of parallel universes in quantum mechanics has been around since 1957,” said Prof Wiseman, who is the senior author of a paper published in the journal Physical Review X.

“In the well-known ‘Many-Worlds Interpretation,’ each universe branches into a bunch of new universes every time a quantum measurement is made. All possibilities are therefore realized – in some universes the dinosaur-killing asteroid missed Earth. In others, Australia was colonized by the Portuguese.”

“But critics question the reality of these other universes, since they do not influence our universe at all. On this score, our ‘Many Interacting Worlds’ approach is completely different, as its name implies.”

“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,” the scientists wrote in the paper.

According to the team, their model of such a ‘many interacting worlds’ approach can reproduce some quantum phenomena – such as Ehrenfest’s theorem, wave packet spreading, barrier tunneling, and zero-point energy – as a direct consequence of mutual repulsion between parallel worlds.

“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.”

Dr Michael Hall of Griffith University, the first author of the paper, said: “the ‘Many-Interacting Worlds’ approach may even create the extraordinary possibility of testing for the existence of other worlds. The beauty of our approach is that if there is just one world our theory reduces to Newtonian mechanics, while if there is a gigantic number of worlds it reproduces quantum mechanics. In between it predicts something new that is neither Newton’s theory nor quantum theory.”

“We also believe that, in providing a new mental picture of quantum effects, it will be useful in planning experiments to test and exploit quantum phenomena.”

The ability to approximate quantum evolution using a finite number of worlds could have significant ramifications in molecular dynamics, which is important for understanding chemical reactions and the action of drugs.

_____

Michael J.W. Hall et al. 2014. Quantum Phenomena Modeled by Interactions between Many Classical Worlds. Physical Review X, 4, 041013; doi: 10.1103/PhysRevX.4.041013