infinite storage soon possible?

[bloodbob]

http://physicsweb.org/articles/news/9/11/13/1

Basicly they've found a way to read a qubit without changing it state. If we could make large devices we could store a near infinite amount of information on a pin head.

A 43 qubit device would hold 1 terrabyte of information every additional qubit would double the device storage capablities.

 

[StefanS]

http://physicsweb.org/articles/news/9/11/13/1

Basicly they've found a way to read a qubit without changing it state. If we could make large devices we could store a near infinite amount of information on a pin head.

A 43 qubit device would hold 1 terrabyte of information every additional qubit would double the device storage capablities.

I am sorry but that's utter bullshit. Not the measurement, but your conjecture.

 

[Guden Oden]

What conjecture?

He's referring to a linked webpage you know.

 

[StefanS]

What conjecture?

He's referring to a linked webpage you know.

He implies there's sg as Infinite quantum storage, which is utter bs. You can't extract more information from a quantum state than classical information. His 43 qubit-example (2^43) is just not possible.
However, you can process more information with a quantum computer than with a classical computer. After your calculation you will extract as much information as classical possible. Thus you save computation time.

The link refers to Josephson contacts, which interesting for another property. Josephson contacts and Squids can be used to create macroscopic qubits / macroscopic accessible qubits. That's is what makes them interesting in contrast to qu-dots, photonic states, ion-traps, etc. The main problem is that because of their macroscopic properties they easily decohere, thus losing the property crucial for quantum computation. Those physicsists in the article managed to create a qubit with J. contacts. However, they have yet to show unitary transformations (aka the calculation operations) with J. contacts, which is a lot more difficult (decoherence!!!).

EDIT: I hope I get my point across, but my Engrish is a little bit whack.

 

[bloodbob]

Well also in that article they claim to be able to read the quantum state of this qubit not destructively. So whats to stop them reading the same register over N times comparing each possible state? I'm sure someone has already come up with bit wise operators.

PS Yeah I know there probably will be ceveat which means it won't work but we can all dream.

 

[StefanS]

Just a sec, I'll read the original articles

 

[Simon F]

If we could make large devices we could store a near infinite amount of information on a pin head.

That would surely have some finite improbabilty and finding a whale and bowl of petunias stored on the pin head would be quite disturbing....

 

[StefanS]

Well also in that article they claim to be able to read the quantum state of this qubit not destructively. So whats to stop them reading the same register over N times comparing each possible state? I'm sure someone has already come up with bit wise operators.

Nope, I've read the original articles and the theoretical paper that proposed such devices: The passage at physicsweb is a bit poorly worded.
First of all, for a quantum non-demolition measurement you need one thing: a constant of motion. Quote from Phys. Rev.A 69,062320: "That the measured observable is a constant of motion imlpies that repeated observations will yield the same result". What is measured here is not a qubit-state in superposition (i.e. |0>+|1>), but a qubit state that is either |0> OR |1>, meaning well defined.
Now, why is this of interest? It preserves the quantum state (i.e. the result): |0> will stay |0> after the read-out. No bit-flip will occur.
Why is this of significance? Let's look at a photon quantum computer: Our state travels through our computer, some calculations take place, a result is reached at our detector. a result is reached at our detector? Let's take a closer look, at what happens: Our photon hits the detector and the quantum state of the result is destroyed. We've now got the result but our quantum state is lost. In other words: Taking the example from above: |0> is lost. We cannot measure the result a second time.
The JJ-devices can preserve the result. As a matter of fact, we can access the result as often as we want.

Little side-note: A machine that would QND-measure a superposition, would work as a perfect cloning machine: unmeasured state A would be copied to state B, state B would be measured. unmeasured state A would be copied to state C, state C would be measured and so. This would break the No-Cloning-Theorem as well as the information accessibility boundary...

 

[Cartoon Corpse]

infinity in (on) a nutshell...not gonna happen.

 

[Deepak]

There is nothing infinite in this universe. Everything is finite.

 

[Cartoon Corpse]

There is nothing infinite in this universe. Everything is finite.

baloney. what contians everything is infinite, even if it's bordered by nothing. has to be. what ever the limit is...counts as something. and whatever limits that. the concept of infinity is simple really.

 

[Deepak]

There can be things close to infinite but not "infinte".

 

[AlphaWolf]

There can be things close to infinite but not "infinte".

Please, stop speaking in absolutes like you know these things for fact.

 

[Cartoon Corpse]

what binds the universe (that which contains the ditritus of the big bang)? nothing? nothing would be something in that case. what limits that? more nothing? infinite. it exists as a concept, it exists as a 'thing'.

 

[sunscar]

Elenventy Billion

Keanu - "I bet eleventy billion dollars."

Trebec - "That's not even a real number"

Keanu - "Yet!"

Replying AlphaSpartan

 

[Guden Oden]

There is nothing infinite in this universe. Everything is finite.

...Except stupidity.

 

[OpenGL guy]

baloney. what contians everything is infinite, even if it's bordered by nothing. has to be. what ever the limit is...counts as something. and whatever limits that. the concept of infinity is simple really.

Doesn't make sense. What is outside the universe? Nothing of course. The universe is all there is as far as we are concerned. It's always going to be a finite volume, however it appears to be expanding. This doesn't make it infinite. Think about the balloon analogy I mentioned previously. If your universe is the surface of the balloon, there is nothing inside or outside that ballon.

The amount of matter in the universe is also finite. Thus, infinite storage is not possible.