The universe just got a whole lot weirder

Posted on 09 Jul 2019 @ 12:22pm by Commander Allyndra illm Warraquim

And you thought that quantum mechanics was as Einstein stated, “Spooky action at a distance,” then my favourite quote from ‘Jurassic Park’, “Hang onto your butts.”

Most of us have heard about quantum entanglement. It is that odd property in which two quantum systems meet and entangle then even across the distance of thousands of lightyears it becomes impossible to measure the features of one system (such as its position, momentum and polarity) without instantly steering the other into a corresponding state. What is now called quantum nonlocality, the eerie link that appears to exist between entangled particles.

The assumption is that the 'nonlocal' part of quantum nonlocality refers to the entanglement of properties across space. The idea that information is transferred at some superluminal speed. And many experiments have shown that. However, what if entanglement also occurs across time? Is there such a thing as temporal nonlocality?

Just when you thought quantum mechanics couldn't get any weirder it turns out the answer to temporal nonlocality is a resounding yes.

Previous experiments involving a technique called 'entanglement swapping' had already showed quantum correlations across time, by delaying the measurement of one of the coexisting entangled particles; but Eli Megidish and his collaborators were the first to show entanglement between photons whose lifespans did not overlap at all.

Here's how they did it.

First, they created an entangled pair of photons, '1-2'. Soon after, they measured the polarisation of photon 1 (a property describing the direction of light's oscillation) – thus 'killing' it.

Photon 2 was sent on a wild goose chase while a new entangled pair, '3-4', was created. Photon 3 was then measured along with the itinerant photon 2 in such a way that the entanglement relation was 'swapped' from the old pairs ('1-2' and '3-4') onto the new '2-3' combo.

Some time later, the polarisation of the lone survivor, photon 4, is measured, and the results are compared with those of the long-dead photon 1 at the beginning of the experiment.

The upshot? The data revealed the existence of quantum correlations between 'temporally nonlocal' photons 1 and 4. That is, entanglement can occur across two quantum systems that never coexisted.

What on does this mean? On the face of the experiment it seems as troubling as saying that the polarity of starlight in the far-distant past – say, greater than twice Earth's lifetime – nevertheless influenced the polarity of starlight falling through your amateur telescope.

Even more bizarrely it implies that the measurements carried out by your eye upon starlight falling through your telescope somehow dictated the polarity of photons more than 9 billion years old.

Lest this scenario strike you as too outlandish, Megidish and his colleagues can't resist speculating on possible and rather spooky interpretations of their results. It means that perhaps the measurement of photon 1's polarisation somehow steers the future polarisation of 4, or the measurement of photon 4's polarisation somehow rewrites the past polarisation state of photon 1.

In both forward and backward directions, quantum correlations span the causal void between the death of one photon and the birth of the other.

In developing his theory of special relativity, Einstein deposed the concept of simultaneity from its Newtonian pedestal. As a consequence, simultaneity went from being an absolute property to being a relative one. There is no single timekeeper for the Universe; precisely when something is occurring depends on your precise location relative to what you are observing, known as your frame of reference.

So the key to avoiding strange causal behaviour (steering the future or rewriting the past) in instances of temporal separation is to accept that calling events 'simultaneous' carries little metaphysical weight which on its own is weird enough.

What it tells me is the universe and the quantum physics underlying it are a whole lot mind blowing then I ever thought but then again maybe it is all relative ;}.

Marilyn

Category: General News

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