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Defeating Heisenberg's Uncertainty Principle
eldavojohn writes "As we strive closer and closer to quantum computing, physics may need to be improved. A paper released in Nature Physics suggests that the limit defined by Heisenberg's Uncertainty Principle can be beaten with quantum memory. From the article, 'The cadre of scientists behind the current paper realized that, by using the process of entanglement, it would be possible to essentially use two particles to figure out the complete state of one. They might even be able to measure incompatible variables like position and momentum. The measurements might not be perfectly precise, but the process could allow them to beat the limit of the uncertainty principle.' Will we find out that Heisenberg was shortsighted in limiting the power of quantum physics or will the scientists be surprised to find that such a theoretical scenario — once conducted — performs unexpectedly in Heisenberg's favor?"
Why do people have to pitch stories like this as ego conflicts? If they get around the uncertainty principle, they'll be erasing it no more than classical mechanics. It's like Relativity is just a more accurate description, an improvement, a super theory on top of Newtonian physics. It doesn't 'defeat' Newton. We use his work as a valid framework all the time anyways. And when we need to go beyond it, we take up Einstein's work. Similarly, getting around the uncertainty principle won't really 'defeat' Heisenberg's work, it'll just build on it. These writers just sound stupid when they frame stories as simple binary conflicts.
Heisenberg's uncertainty principle is still a fundamental cornerstone in quantum physics. Incompatible observables remain incompatible. What the article says isn't that the principle is wrong, but that there is a work-around for a technical problem which the principle was causing. Much the same way the invention of airplanes did not imply gravity is wrong.
That's all I can say without seeing some math.
GAAH! MY PRINTER IS ON FIRE!!! PUT IT OUT! PUT IT OUT!
So, perhaps if you took two entangled particles, and measured the momentum of one, and the position of the other, you could extrapolate the total state of one of them. JUST LIKE THE SUMMARY SAYS
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
It's more like this:
I want to know the name and date of birth of a particular person, but I'm only allowed to ask one question per person. If that person has a twin, I can ask the person i'm curious about their name, and the twin their age, thus circumventing the one question limit in this case.
It's sort of a cheat, it probably can't be used to get arbitrarily accurate information regarding a particle of interest, and it may only work on a small subset of particles (they need to have entangled partners).
The Heisenberg uncertainty principle puts a well-defined, quantitative lower limit on the certainty for certain pairs of variables. For example the uncertainty in momentum multiplied by the uncertainty in position for a particle must be greater than or equal to h/4pi. Breaking that limit would break Heisenberg, even if the results still weren't totally totally certain, accurate and precise.
No kidding!!! What do you say at this point?
How can you be so certain?
Remember to maintain your supply of
You are right. I know the paper well since I work in this area, and the article and summary are VERY misleading. Heisenberg's uncertainty principle is perfectly safe as originally articulated -- this is merely a rephrasing of it, and an extension of it. It is a nice paper, but I wish journalists wouldn't try to sensationalise things by saying Einstein/Newton/Heisenberg/CowboyNeal is wrong... Here, I suspect the authors are slightly to blame for this -- note the peer-reviewed article is much more conservative and careful than arxiv version (which is perhaps what led to the misleading popular science article): http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys1734.html http://arxiv.org/abs/quant-ph0909.0950
Because they know your speed, but not your position. That's why they have to mail the ticket to your house.