Quantum ghosts are helpful

Apr 27, 2009
Quantum ghosts are helpful

(PhysOrg.com) -- The idea that far distant particles can somehow 'talk' to each other worried Einstein so much that he called it 'spooky action at a distance'.

Having confirmed its existence, scientists today are learning how to use this 'spooky action' as a helpful tool. Now a team of physicists at the University of Bristol and Imperial College London have harnessed this phenomenon to shed light on another unusual and previously difficult aspect of - that of distinguishing between two similar quantum devices.

In the everyday world any process can be considered as a black box device with an input and an output; if you wish to identify the device you simply apply inputs, measure the outputs and determine what must have happened in between.

But quantum black boxes are different. Distinguishing between them is impossible using only single particle inputs because the outputs are not distinguishable: a fundamental consequence of the laws of quantum mechanics is that only very few states of a quantum particle can be reliably distinguished from one another.

The Bristol-Imperial team has shown how to get around this problem using 'spooky action'.

Anthony Laing, PhD student in the Department of Physics, who performed the study, said: "Apart from providing insight into the fundamentals of quantum physics, this work may be crucial for future quantum technologies.

"How else could a future quantum engineer build a quantum computer if they can't tell which circuits they have?"

The new findings have implications for our understanding of as well as the emerging potential of quantum information science.

More information: The paper in is published online ahead of print, 24 April 2009, http://link.aps.org/abstract/PRL/v102/e160502 .

Source: University of Bristol (news : web)

Explore further: Researchers find qubits based on trapped ions offer a promising scalable platform for quantum computing

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User comments : 10

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LuckyBrandon
5 / 5 (1) Apr 27, 2009
maybe the spooky action at a distance philosophy also speaks to why we get a gut feeling when our kids are up to no good :D
laserdaveb
5 / 5 (2) Apr 27, 2009
alas..PRL.."moving physics forward"... for a price
this report tells us nothing
Auxon
not rated yet Apr 27, 2009
alas..PRL.."moving physics forward"... for a price







this report tells us nothing








Yeah, I was going to say basically the same thing. The article says, "entanglement could be used to figure out things about quantum states which we can't figure out yet." Sad ... not even a hint of how it would be used.
holoman
not rated yet Apr 27, 2009
This might give a hint of what direction things
might go.

http://colossalst...gled.htm
Alizee
Apr 27, 2009
This comment has been removed by a moderator.
Alizee
Apr 27, 2009
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LuckyBrandon
5 / 5 (2) Apr 27, 2009
"The observation of quantum particle is analogous to situation, when sailor touches the boat for a moment, thus exchanging some kinetic energy with it. What will happen, after then? The wharf and boat will start to oscillate at phase. It means, the sailor will keep his relative position with respect to boat, so he cannot detect any boat wobbling anymore, because he moves by the same way. We can say, the wave function of boat has collapsed from perspective of that sailor."

This is not true...get on a boat and hold the side, you damn sure still feel the movement of the boat, and see it, it is only your perception that has changed, because you have changed the angle of which you are viewing the boat. Ask anyone who has ever gotten sea sick...they stand at the rails, and they dont feel better, they still puke all over the side of that fresh white paint. Get on a boat and try it. If htis were true, they should feel better at the rails, and no longer ralph all over anyone or anything near them. No matter what the tiresome AWT says, you cannot change the fact that there is NO change in the movement or oscillation of the boat when someoen touches the rail, in order to do that, youd have to invoke newtons laws that state that an object in motion stays in motion until acted upon by an outside force...more important than that, that force must be equal to or greater than he force creating the movement to begin with, or else it is simply knocked aside as if it wasnt there. Think of a soccer ball that was just kicked...the grass doesnt stop the movement (immediately anyways, given enough time, drag and friction kick in stopping it of course) or oscillate with the movement of the ball, which gives much more resistence than a sailor touching the rails of a boat, instead, the grass gives way to the ball until the next player kicks it again, beginning the momentum all over.

Alizee with her boat examples...lol

You cannot bypass known laws of motion by using AWT. At a quantum level, I don't think something like AWT is worth anything, as it cannot be used to explain the physical and quantum worlds, as they are too different to do that with.


I am sick of the phrase "by AWT", i swear...
Alizee
Apr 27, 2009
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Alizee
Apr 27, 2009
This comment has been removed by a moderator.
LuckyBrandon
5 / 5 (1) Apr 27, 2009
Dont worry Alizee, I always like your analogies and explanations :)

Heres my responses for ya :)

A legend has indeed been born, as I always remember you for your boat analogies, and my quotes of the past of you liking the boat analogies. Legend by any definition within my memory :)

From a particle and quantum level, I admit, the analogy doesnt work so well. I do figure at some point though, since the quantum and physical world are entangled, and we will discover one day how, that the analogy in 20 yrs may very well be valid :) Lets wait 20 and see then :)

Good explanation of the grass movement analogy..I like

The reason I'm sick of the "By AWT" quote is because everyone defending/introducing/speaking to AWT begins their sentence in the exact same way. It would be nice to see it start with something like "Within the aether wave theory" or something of the like, just for a change. Merely a grammatical preference there is all.

My thought on your last post though, is that weight attributed to the sailors body mass does in fact change things, but my point was that his movement, and sense of movement, will not change just because hes on the rails.

Its my 8th wedding anniversary though, and I'm drunker n drunker the more I type, so maybe that doesnt make sense :)
SmartK8
not rated yet Apr 28, 2009
LuckBrandon: Well said! Let's wait and see. Maybe the next generation religion prayers will start with "By holy AWT..".
Alexa
5 / 5 (1) Apr 28, 2009
. we will discover one day how..
It's discovered already. After all - if you don't believe in boats and droplets, here are experiments, which are confirming this model directly.

http://www.physor...511.html

. next generation religion prayers..

Well, on the contrary. AWT forces you to understand things, not to believe in abstract postulates. AWT is nothing for religious physicists, but for people, who are able to explain things in illustrative way.

..it would be nice to see ..
Maybe it would be nice for you, but not for Google keyword searchers, for example. My congrats. 4 your 8th wedding anniversary anyway.

Frankly, I don't understand the people, why they're so hostile against every new interpretation of quantum mechanics. If nothing else, it would enable you to think about it in new way at the moment, when intuitive insight is missing.

One would expect, people like you should be thankful - not impertinent.
LuckyBrandon
not rated yet Apr 28, 2009
Oh I will read everything and make determinitations. I'm not against one way or another. If I can put it in a lab and reproduce it, or observe it with little room for mistaken identidy in whats being observed, then I am all for calling something a fact.
superhuman
not rated yet May 01, 2009
The observation of quantum particle is analogous to situation, when sailor touches the boat for a moment, thus exchanging some kinetic energy with it. What will happen, after then? The wharf and boat will start to oscillate at phase.


There are problems with this analogy.

As boats and wharfs are much bigger then water wave lengths they will oscillate with their own specific frequencies depending on their dimensions and mass among other things, it is certainly not a trivial situation to model.

The sailor will have to act with a significant and periodically changing force to keep the two bodies oscillations in phase, in reality he would probably have to weld them together. In any case the phase would start to deviate the moment the boat and the wharf are no longer linked.

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