A Whole New Model of Quantum Physics Suggests the Future Can Change the Past
If you thought physicist Sabine Hossenfelder was exaggerating when she claimed that theoretical physics is going off the rails and bringing the whole discipline of physics down with it, a group of scientists claiming that the future influences the past may change your mind.
The group's theory revolves around the idea of "retrocausality," which aims to explain one of the central mysteries of quantum physics: quantum entanglement.
At the heart of what makes quantum physics so confusing (and seemingly insane) is the idea that the actual properties of particles change when they're observed.
Until then, they seem to exist in a state of blurry possibilities, where they can, for example, be spinning in both directions and neither all at once.
So is this seemingly paradoxical "quantum state" a real phenomenon, or just a product of a flawed view of physics?
Those two potential options are the "realist" and non-realist viewpoints on the quantum state, and strangely enough, the concept of retrocausality falls into the "realist" camp.
Retrocausality is meant to explain one of the stranger manifestations of the quantum state, where two entangled particles are moved apart and any changes in one seem to change the other, regardless of the distance between them.
It's unknown how the two particles are able to "communicate" across this distance, and the concept seemed so ridiculous to Albert Einstein that he called it "spooky action at a distance."
Retrocausality, however, says it's not a matter of one particle acting on another across distance; it's about one particle acting on the other across time.
According to retrocausality, decisions made in the present (such as choosing a measurement method for an entangled particle) can retroactively change the properties of the other entangled particle.
"There is a small group of physicists and philosophers that think this idea is worth pursuing, including Huw Price and Ken Wharton [a physics professor at San José State University]," Matthew S. Leifer, of Chapman University, told Phys.org.
"There is not, to my knowledge, a generally agreed upon interpretation of quantum theory that recovers the whole theory and exploits this idea. It is more of an idea for an interpretation at the moment, so I think that other physicists are rightly skeptical, and the onus is on us to flesh out the idea."
Hopefully they find a way to test this theory—otherwise, theoretical physics may have officially become a bunch of scientists sitting around and saying "Wouldn't it be cool if...?"
Of course, if retrocausality ends up being nothing more than another grandiose thought experiment, just remember: The entire universe is conscious, and humans are all manifestations of its multiple personalities.
So there you have it: either way, things are still pretty complicated.