Dear Atheists, I'm not going to ask about God...?

If they existed in other, imperceptible dimensions, they wouldn't have much of anything to do with us, would they? "Ghost" stories are all about dead people and their unresolved issues. That's not interdimensionality. That's storytelling and superstition. Quantum physicists are looking for quarks, not phantoms or spirits. It's the New Age/TM and mystical crowd that are stealing quantum physical terminology to justify their hallucinatory woo-woo. There is a practical limit to the "anything".