There have been some similar ideas, but not related to MWI—as DanielLC says, the “distance” that separates two different states of the universe does not behave like we commonly imagine distance between “parallel worlds” to behave.
However, something that can behave like that is these extra spatial dimensions proposed by string theory, brane theory, etc. See wikipedia. I’m sure someone has proposed this as an explanation for dark matter.
There have been some similar ideas, but not related to MWI—as DanielLC says, the “distance” that separates two different states of the universe does not behave like we commonly imagine distance between “parallel worlds” to behave.
However, something that can behave like that is these extra spatial dimensions proposed by string theory, brane theory, etc. See wikipedia. I’m sure someone has proposed this as an explanation for dark matter.