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Time from quantum entanglement: an experimental illustration

Ekaterina Moreva, Giorgio Brida, Marco Gramegna

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Vittorio Giovannetti, Lorenzo Maccone, Marco Genovese

2013 · arXiv

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From the abstract

In the last years several theoretical papers discussed if time can be an emergent property deriving from quantum correlations. Here, to provide an insight into how this phenomenon can occur, we present an experiment that illustrates Page and Wootters' mechanism of "static" time, and Gambini et al. subsequent refinements. A static, entangled state between a clock system and the rest of the universe is perceived as evolving by internal observers that test the correlations between the two subsystems. We implement this mechanism using an entangled state of the polarization of two photons, one of which is used as a clock to gauge the evolution of the second: an "internal" observer that becomes correlated with the clock photon sees the other system evolve, while an "external" observer that only observes global properties of the two photons can prove it is static.

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phailhaus
Neutral mention · rule
One experiment suggests that time is an emergent property of quantum entanglement. [1] "A static, entangled state between a clock system and the rest of the universe is perceived as evolving by internal observers that test the correlations between the two subsystems. We implement this mechanism using an entangled state of the polarization of two photons, one of which is used as a clock to gauge the evolution of the second: an "internal" observer that becomes correlated with the clock photon sees the other system evolve, while an "external" observer that only observes global properties of the two photons can prove it is static." [1] https://arxiv.org/abs/1310.4691
ztjio
Neutral mention · rule
The position that time is not a localized phenomenon is preposterous. Given the observations of relativity and the effect that local gravitational force has on passage of time, and more recent experiment and theory about time actually arising as an effect of quantum entanglement (https://arxiv.org/abs/1310.4691), to presume in the context of such a big, extremely-theoretical idea that time is not local is plain nuts. It's not so hard to imagine that the rules of relativity are imposed and that outside of that imposition, they don't exist or are discontinuous to some degree. Indeed, it doesn't even take any imagination if one considers the theories and research related to what I linked above. So personally I'd dismiss the conclusion given its predication on this idea. To me, time not being local is the controversial position.
john_b
Neutral mention · rule
Or you could just, you know, check the published experimental results: http://www.technologyreview.com/view/512281/chinese-physicis... Physicists are increasingly convinced that time is an emergent property that arises due to low level quantum effects, principally entanglement [1]. The experiment in the Ars Technica article is the equivalent of the universe using lazy evaluation. It's really not so mysterious if you think outside the box of classical physics. Regarding sending information back in time, from what I've read physicists are divided on the issue. Most agree that sending matter back in time is impossible, but information is still up for debate. In this…
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particular experiment, however, any past observer who measured the information sent back in time would have collapsed the entangled quantum state and prevented the experiment from being conducted successfully. So being able to "successfully" send information back in time doesn't appear too useful if you can't read it. [1] http://arxiv.org/abs/1310.4691

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