2017-06-19 at 5:58 PM UTC
'Information carried in the quantum state of a particle cannot be copied or measured, without the information itself being destroyed.'
this is from an article I read about quantum computing. from what this statement says, and how i translate the rest of the article, the information is literally useless because it cant be utilized in any way...without being destroyed.
am I missing something here?
2017-06-19 at 6:07 PM UTC
by attempting to measure a particle you inevitably change its position, yes.
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2017-06-19 at 6:08 PM UTC
You are missing the part where you sexually harrass the article.
Maybe you should post the article for a further explanation but i would imagine the point is that any means of measuring or copying that specific quantum information will destroy the original copy of the information. I dont know man. Im not a fucking physicist.
2017-06-19 at 6:21 PM UTC
particles can be in two places at once. true fact.
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2017-06-19 at 6:37 PM UTC
Originally posted by infinityshock
i would have if i could have.
im on a PC that isnt connected to the PC that I read the article on…and cant use my phone to take a pic.
well google the article on the pc you are on then. its not quantuum physics for christs sake.
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2017-06-19 at 8:40 PM UTC
Ok so I don't remember the password to the thing I use to access academic shit rn. I'm going to try to explain a bit by guessing based off the abstract and the excerpt you referred to. Here is the situation with regards to "information trapped in the quantum state" being useless.
I'm sure you know about spin, so I won't waste time explaining that. When two particles are entangled, then their wavefunctions collapse, they will collapse into equivalent and opposite states of spin due to conservation of energy. We cannot influence this spin (it is confirmed as being indeterministic due to Bell's inequality) and predict it's specific outcome, we can just model it as a probability field. This means we cannot communicate any new information (not really) using quantum entanglement.
The classic example used to explain why you can't "communicate" with it is of the red and blue ball. The nature of this is essentially that, imagine if you and a bro have a red and blue ball. You out both balls in a separate box. Then you put the boxes in a bigger box, and shake it up, lovingly holding hands and gazing into each other's gay eyes. At this point, neither of you will know which ball is in which box. Then you pick your box and your bro takes the other box. Then you go 200099999938828383838338 light-years away from each other. You open the box, and see that your box has a blue ball in it. In this way, you have "communicated faster than light" that your bro has the red ball.
Normally, this means you can't use it for any useful communication, however since it is random, you can theoretically use it to solve the problem of cryptographic key exchange. The linked article tries to show a proof of concept of this.
I'm not sure why they believe that excerpt you gave, but it's possible what they mean is that the "potential information" that a particle in superposition carries is destroyed when it's wavefunction collapses (i.e. you measure it's spin). I'd have to read the article itself for context but it doesn't seem to be saying that quantum computing is useless.
2017-06-19 at 11:28 PM UTC
tl;dr: the resultant can be measured, not the particles themselves, the particles can only have estimated parameters
didn't even read the article but this is probably what it meant
