Quantum weirdness: entanglement across time periods (Introduction)

by David Turell , Thursday, April 19, 2018, 18:11 (2410 days ago) @ David Turell

Israeli research has entangled unrelated photons from different time periods:

https://aeon.co/ideas/you-thought-quantum-mechanics-was-weird-check-out-entangled-time?...

"Up to today, most experiments have tested entanglement over spatial gaps. The assumption is that the ‘nonlocal’ part of quantum nonlocality refers to the entanglement of properties across space. But what if entanglement also occurs across time? Is there such a thing as temporal nonlocality?

"The answer, as it turns out, is yes. Just when you thought quantum mechanics couldn’t get any weirder, a team of physicists at the Hebrew University of Jerusalem reported in 2013 that they had successfully entangled photons that never coexisted. 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.

***

"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.

***

"The lesson carries over directly to both spatial and temporal quantum nonlocality. Mysteries regarding entangled pairs of particles amount to disagreements about labelling, brought about by relativity. Einstein showed that no sequence of events can be metaphysically privileged – can be considered more real – than any other. Only by accepting this insight can one make headway on such quantum puzzles.

***

"These findings drive yet another wedge between our beloved classical intuitions and the empirical realities of quantum mechanics. As was true for Schrödinger and his contemporaries, scientific progress is going to involve investigating the limitations of certain metaphysical views. Schrödinger’s cat, half-alive and half-dead, was created to illustrate how the entanglement of systems leads to macroscopic phenomena that defy our usual understanding of the relations between objects and their properties: an organism such as a cat is either dead or alive. No middle ground there.

"Most contemporary philosophical accounts of the relationship between objects and their properties embrace entanglement solely from the perspective of spatial nonlocality. But there’s still significant work to be done on incorporating temporal nonlocality – not only in object-property discussions, but also in debates over material composition (such as the relation between a lump of clay and the statue it forms), and part-whole relations (such as how a hand relates to a limb, or a limb to a person). For example, the ‘puzzle’ of how parts fit with an overall whole presumes clear-cut spatial boundaries among underlying components, yet spatial nonlocality cautions against this view. Temporal nonlocality further complicates this picture: how does one describe an entity whose constituent parts are not even coexistent?

"Discerning the nature of entanglement might at times be an uncomfortable project. It’s not clear what substantive metaphysics might emerge from scrutiny of fascinating new research by the likes of Megidish and other physicists. In a letter to Einstein, Schrödinger notes wryly (and deploying an odd metaphor): ‘One has the feeling that it is precisely the most important statements of the new theory that can really be squeezed into these Spanish boots – but only with difficulty.’ We cannot afford to ignore spatial or temporal nonlocality in future metaphysics: whether or not the boots fit, we’ll have to wear ’em."

Comment: Our universe is grounded in quantum reality. We will stay confused, perhaps as God intended, until we understand it, if we ever can. God must exist in the layer of quantum reality that we can currently only glimpse at across the wall of uncertainty. Look at the diagram to understand how they conducted the experiment.