QuantumMechanics Braces for the Ultimate Test

[Rolci]

Here's something I found from years ago yet it's nowhere on UM. I stumbled upon it while researching nonlocal connectivity, namely Bell's Theorem. The article, though not the latest, is still very intriguing, and the race for results is, to the best of my knowledge, still ongoing. Anyone aware of any updates please post here.

Physicists are on a quest to build the ultimate quantum cryptography system: one that users could trust implicitly, even if they had bought it from their worst enemy. First, however, they have to plug a few stubborn holes in one of the bedrocks of modern physics: quantum mechanics. The microscopic world that quantum mechanics describes is a bizarre place where nothing is certain and the act of observation changes things. Over the past 40 years, that description has been put to the test in a series of elegant experiments that have shown it to be true.

Source: http://www.yumpu.com...ence-news-focus

Edited July 31, 2014 by Saru
Edited text length - please do not copy and paste entire articles

[Calle]

to much to read, bookmarked for later

[Rolci]

A follow-up to this topic, a new article that appeared in the latest issue of the New Scientist:

http://www.newscientist.com/article/mg22329794.600-quantum-split-particle-this-way-properties-that-way.html

[StarMountainKid]

A follow-up to this topic, a new article that appeared in the latest issue of the New Scientist:

Is anyone a subscriber to NewScientist so this article can be shared here?

But he adds that it remains possible that hidden variables produced before the experiment began - perhaps even reaching as far back as the big bang - are predetermining all our actions. “It will be impossible to test against that type of super determinism,” he says.

From Rolci's first link.

This is interesting to me, because I consider time as past, present and future to be predetermined as a whole.

Edited July 28, 2014 by StarMountainKid

[Rolci]

Is anyone a subscriber to NewScientist so this article can be shared here?

Obviously I'm not allowed to paste the entire article here but I can email "something" to anyone interested.

[StarMountainKid]

Separating a neutron's properties from the neutron itself. Very strange. What does this mean for our understanding of reality? How does one define a neutron if it is separated from its properties? How are the properties of elementary particles, even atoms, related? How do these properties choose or 'stick' to the neutrons?

Lots of questions in my mind.

[shrooma]

Separating a neutron's properties from the neutron itself.

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" as if you took one path and your personality another."

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[White Crane Feather]

I'm no physicists, but it sounds like to many loopholes to me. Having a substrate "code" of nature I think is probably a given. Einsteins instincts tend to be correct, but randomness can be built into a code as well. If its not, then once we decipher the substrate mechanics we should be able to calculate the future there by allowing us to change it making the code no longer valid. This is why determinism creates a paradox that collapses determinism itself.

[badeskov]

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" as if you took one path and your personality another."

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Somehow I often find myself in that very peculiar position.

Typically after leaving the pub.....

Cheers,

Badeskov

[Leonardo]

Separating a neutron's properties from the neutron itself. Very strange. What does this mean for our understanding of reality? How does one define a neutron if it is separated from its properties? How are the properties of elementary particles, even atoms, related? How do these properties choose or 'stick' to the neutrons?

Lots of questions in my mind.

While I do not doubt the results the scientists who conducting the experiment being referred to here measured (i.e. their instruments measured two different values independently), I do doubt their conclusion of "separation of property from particle".

However, if said properties are not intrinsic to objects, but epiphenomenon arising from the interaction of the object with a field (such as mass is thought to be), then I can envisage the possibility of measuring the two independently. So, rather than "separating particle and property" they "isolated particle from field".

Edited July 31, 2014 by Leonardo

[sepulchrave]

While I do not doubt the results the scientists who conducting the experiment being referred to here measured (i.e. their instruments measured two different values independently), I do doubt their conclusion of "separation of property from particle".

I agree, I think the authors have been a bit liberal with their language.

The actual paper is available here (I think it is open access). Basically this result depends on weak measurements, wherein the expectation value for the location of the particle and the spin projection of the particle of an ensemble are found to indicate that the ``average'' particle was some how separated from its spin.

This is in complete agreement with elementary quantum theory.

A weak measurement does not cause a wave function collapse and therefore should not be considered to be a concrete measurement of any aspect of any single particle.

I found the paper linked above quite interesting and well written, and I highly recommend reading the paper to anyone who has a working knowledge of elementary quantum mechanics and bra-ket notation.