Quantum ghosts are helpful

April 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: Quantum cryptography: No Signaling and quantum key distribution

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5 / 5 (2) Apr 27, 2009
alas..PRL.."moving physics forward"... for a price
this report tells us nothing
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.
not rated yet Apr 27, 2009
This might give a hint of what direction things
might go.

Apr 27, 2009
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Apr 27, 2009
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Apr 27, 2009
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Apr 27, 2009
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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..".
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.


. 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.
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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