Wiseman and colleagues have proposed that there exists "a universal force of repulsion between ‘nearby’ (i.e. similar) worlds, which tends to make them more dissimilar." Quantum effects can be explained by factoring in this force, they propose.
Whether or not the math holds true will be the ultimate test for this theory. Does it or does it not properly predict quantum effects mathematically? But the theory is certain to provide plenty of fodder for the imagination.
For instance, when asked about whether their theory might entail the possibility that humans could someday interact with other worlds, Wiseman said: "It's not part of our theory. But the idea of [human] interactions with other universes is no longer pure fantasy."