Quantum computer solves problem, without running

[scott1]

combining quantum computation and quantum interrogation, scientists at the University of Illinois at Urbana-Champaign have found an exotic way of determining an answer to an algorithm – without ever running the algorithm.

http://www.physorg.com/news11087.html
I don't understand how they can do this.

 

[pallidin]

Very interesting! I found the following in the link you provided:

Through clever use of beam splitters and both constructive and destructive interference, the researchers can put each photon in a superposition of taking two paths. Although a photon can occupy multiple places simultaneously, it can only make an actual appearance at one location. Its presence defines its path, and that can, in a very strange way, negate the need for the search algorithm to run.

"In a sense, it is the possibility that the algorithm could run which prevents the algorithm from running," Kwiat said. "That is at the heart of quantum interrogation schemes, and to my mind, quantum mechanics doesn't get any more mysterious than this."

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Very bizarre indeed.
Pallidin

 

[leandros_p]

A classical algorithm is a road map of decision making process. Following the road map of decision making and arriving at the next node of the road map we found ourselves in a new position that is caused by the path of the previous positions and which will bring us to the next position. By this process, in order to arrive at the final destination/position of the decision making process we follow a path of positions like following a chain of positions where the previous positions guides to the next position. Each previous position is causing our advance to the next position, according to the algorithmic evaluation that takes place in every position, forming a chain of applied rules that effect the trail of decision making.

The algorithm is providing the causal rules that propel us from the previous position to the next one, until the final destination of decision making process is being reached. Causal rules can be chained, since effects can in turn be causes of other effects, therefore a classical algorithm is a map that provides the necessary rules for every position of the decision making path.

But, the combination of quantum computation and quantum interrogation is more than a map of applied rules. Quantum "algorithm" is by itself the wholeness of the decision making process. It does not provide a step by step map of decision making path. It contains the decision making mechanism of chained causal rules as singular intrinsic possible state. Each position of the decision making process is unified with all subsequent positions that are effected in the chain of causal rules in the decision making path, constituting the wholeness of a single possible result in one position of the applied quantum algorithm.

In this context, for quantum algorithm/interrogation , even the first position of the road map of the decision making process is synonymous with every other position of the road map of the decision making process; the first position is even synonymous with the last position. So, arriving at the first position of the road map of the decision making process of quantum algorithm results in arriving at the final position of the road map of decision making process: we arrive at the end being immobile at the beginning !

This paradox is not magic; it is the aftermath of physical information being processed by physical process that we call quantum physics. That is, quantum algorithm process physical information with the “process engine” of reality. And because reality is not produced by following a road map defined by causal rules we profit from the “process engine” of reality that contains and unifies at once the “cause” and the “effect” at the same position.

Leandros

Quantum Zeno effect: http://en.wikipedia.org/wiki/Quantum_Zeno_effect

 

[alfredblase]

OMG. QM is horrible! stop it! stop it! stop messing with my mind! I don't like it! (that was after reading the QM zeno link)

actually I have a proposal: WF = WTF?!

 

[Schrodinger's Dog]

Technology has been the never ending search to explain and to make life easier, this is the ultimate in lazy mankinds passage to invactivity. Now not only do we not have to do very much we don't have to do anything at all, BRAVO modern science your living the dream. Now if we can make it so that we actually have to do less than nothing to learn anything we can recover all those lost moments in experimentation, and put our feet up and watch TV or read that copy of the Bagavita we've been meaning to get round too

One thing in this article did make me laugh though.

"One day, Boris, man will peer into his microscope
and find himself staring directly into the eye of God.
And the first one to blink will lose his testicles."
-Peter O'Toole in "Creator"

 

[dav2008]

Very interesting! I found the following in the link you provided:

Through clever use of beam splitters and both constructive and destructive interference, the researchers can put each photon in a superposition of taking two paths. Although a photon can occupy multiple places simultaneously, it can only make an actual appearance at one location. Its presence defines its path, and that can, in a very strange way, negate the need for the search algorithm to run.

"In a sense, it is the possibility that the algorithm could run which prevents the algorithm from running," Kwiat said. "That is at the heart of quantum interrogation schemes, and to my mind, quantum mechanics doesn't get any more mysterious than this."

----------
Very bizarre indeed.
Pallidin

Oh that's awesome :D

I am currently enrolled in UIUC and Kwiat was my instructor for Quantum Physics and is currently my instructor for Thermal Physics. He seems like an interesting guy. He's got the whole suspenders and bowtie thing going for him

 

[koantum]

Some of you may find my discussions of the following experiments helpful in this context:

1. a http://thisquantumworld.com/scat.htm"
2. the http://thisquantumworld.com/ghz.htm"
3. an experiment illustrating http://thisquantumworld.com/bell.htm" ,
4. the http://thisquantumworld.com/ev.htm" of Elitzur and Vaidman.

 

[LnGrrrR]

<--- after reading Zeno effect

Wow. I'm going to have to apologize to my mom. :(

I guess a watched pot really DOESN'T boil... ;)