Quantum Time: This Quantum Theory Says Time Can Flow Backward. Is This Where The Flow Of Existence Comes From?

physics throws all the rules of classical physics out the window. In the
quantum world, particles can pass through solid walls, be in two places at
once, and communicate over an infinite distance. And, if a handful of
physicists are right, they can affect the past just as easily as they affect
the future.

That's a
theory known as quantum retrocausality, and researchers have good reasons to
believe it's true.

One of the
fundamental oddities about quantum physics is the principle of superposition,
which says that a particle exists in multiple states at once until it's
measured. That means that while classical physics deals in solid numbers,
quantum mechanics deals in fuzzy probabilities. There's an ongoing debate,
however, about why that is: is it that we just don't have the right precision
to understand the true states of individual particles so they just look fuzzy,
or is the reality of the quantum world that everything is fuzzy until it's

In 2012,
physicist Huw Price argued that if the latter is true — if the quantum world
really is a soup of superposition — then it opens the door to some intriguing
possibilities. Neither classical nor quantum physics say time can only go

In theory,
all physical processes can run forward and backward; it's just that in
classical physics, the second law of thermodynamics puts a stop to things like
time going backward and toast un-burning. But that red light doesn't apply to
quantum mechanics. So if the quantum world really does involve multiple states
and time can flow backward, Price says, measuring the state of a particle today
could technically affect its state in the past.

If Price is
right (ha!), it could be the solution to something that has puzzled physicists
all the way back to Albert Einstein: quantum entanglement, which Einstein
ridiculed as "spooky action at a distance." The idea is that you can
link the states of two particles so that even when they're separated over an
infinite distance, the state of one affects the state of the other. The problem
with this is that it seems to require information to be sent faster than the
speed of light, which is impossible. That's what's so "spooky" about

In 2017,Matthew Leifer and Matthew Pusey applied Price's idea to the puzzle of quantum
entanglement. If the current state of a particle can affect its state in the
past, then maybe quantum entanglement isn't action at a distance but action
back in time. That is, if time can run backwards, a particle can take the
action of its measurement — the event that makes it "choose" a state
— back in time to when it was linked with its partner. Trading
faster-than-light travel for time travel doesn't sound like much of an
improvement, but when it comes to the rules of quantum physics, it solves a lot
of problems.

Of course,
there are huge caveats. First, this doesn't mean that a physicist could send a
message to her younger self, or that you could go back in time to kill Hitler.
We still live in the macroscopic world of classical physics, where entropy is
still a thing. Second, this is a very fringe idea in the physics world.
"There is not, to my knowledge, a generally agreed upon interpretation of
quantum theory that recovers the whole theory and exploits this idea
Leifer told Phys.org. "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

Can't get
enough quantum physics? Check out "The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos" by physicist Brian Greene. We handpick
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Via Curiosity.