Uncertainty Principle Violated

Physicists at the University of Toronto in Canada have demonstrated a violation of Heisenberg's Uncertainty Principle, one of the central ideas of quantum mechanics, using 'weak measurement'.

BBC News article

Abstract of original paper in Physical Review Letters

Unfortunately, neither the article nor the abstract goes into much detail about what has actually been done. No doubt more information will emerge later; if someone has a subscription to PRL they'll be able to read the paper in full and share the information, which would be helpful. The authors point out that the fundamental uncertainty that affects quantum measurements, and thus the way we apprehend reality, still stands; but it may not be such an obstacle to knowledge as was previously thought.

Incidentally, the BBC article contains an error:

Heisenberg's uncertainty principle, as it came to be known later, started as an assertion that when trying to measure one aspect of a particle precisely, say its position, experimenters would necessarily "blur out" the precision in its speed.

As most people interested in the subject know, what is 'blurred out' isn't always 'speed' (actually momentum); it depends on what's being measured.

Right now, this seems to be of most import to quantum cryptographers. But here on ATS, it will be amusing to see how our New Age 'quantum consciousness' fans respond to the news...

Off topic, but the title of this sounds like something criminal happened.
Violated?

You just can't trust those scientists; all those hours spent alone, away from people with those beady little eyes of theirs.

On a serious note, this news is pretty cool. Heisenberg broken? Perhaps we can break Einstein and some others as well. That would be cool.

Onward Science!

For fun, here's a comic of a little bit of relevance:



S&F btw!

There is not even enough information to discuss this. What exactly do they mean "blur out"? This doesn't make much sense.

Photons can be prepared in pairs which are inextricably tied to one another, in a delicate quantum state called entanglement, and the weak measurement idea is to infer information about them as they pass, before and after carrying out a formal measurement.

How does this make Heisenberg wrong?

Here and Here are some more articles on it, I'm still trying to digest it in my own feeble way so I can't really comment on it as yet

The uncertainty priciple has been found to be accurate in many experiments and tests, this is an amazing occurance indeed.

reply to post by Astyanax

As most people interested in the subject know, what is 'blurred out' isn't always 'speed' (actually momentum); it depends on what's being measured.

What are other examples of variables of the Heisenberg Uncertainty Principle?

But here on ATS, it will be amusing to see how our New Age 'quantum consciousness' fans respond to the news...

Seems those people got under your skin. Also seems like you want to suggest that this group of people will not be pleased with this news.

In your words, how do you think it will destroy their views? What is the nail in the coffin of "quantum consciousness" here?

reply to post by BuckWilder

What are other examples of variables of the Heisenberg Uncertainty Principle?

If you try to measure momentum, it's position that gets 'blurred out'.

Seems those people got under your skin. (blah blah) What is the nail in the coffin of "quantum consciousness" here?

Seems you're trying to pick a fight. Get lost.

The thread title is so salacious....

For those trying to wrap their minds around the principle:

Imagine that you are a giant. You want to see the inside of a fairy house. You try to get in the door, and you distort it. When you get in you knock over the chair. When you twitch wrong, you put a hole in the wall.

You can make observations about the fairy's house based on all these things. However, no matter what you do you are in some way disturbing the natural environment of the house so you can never be totally sure that you are seeing the house as it would be with you - the giant - in it.

esciencenews.com...

So they are pinging a pinging a photon over and over to see how it is impacted by the measurement, and seeing that it isn't disturbed as much as the principle says it should be.

What I would be interested to know is if the disturbance is showing up somewhere else / on something else that isn't being measured. They didn't knock over the fairy chair, but when the giant coughed their neighbour's wall shook.

reply to post by Astyanax

If you try to measure momentum, it's position that gets 'blurred out'.

So what does this mean with regards to debunking quantum consciousness?

Seems you're trying to pick a fight. Get lost.

Really me? I was under the impression that you were in fact calling out people with opposing views, but I might be mistaken.

Get lost? That's not very nice Astyanax. Why not just talk about the subject matter?

Is there some sort of problem? I thought this was going to be amusing for ya.

Also, I'd appreciate it if you didn't falsify my qoutes by adding text to them.

reply to post by Astyanax

The complete August 2012 paper is freely downloadable in PDF format.

Violation of Heisenberg's Measurement-Disturbance Relationship by Weak Measurements

I have not read the paper yet so I do not have any other comments at this time.

Best regards,
Z

The thread title is incorrect/incomplete I think. The uncertainty principle is not violated. The assumption that a measurement has to disturb the system is shown to be wrong by using weak measurement.

The idea behind weak measurement is not to change the measured system by exploiting the uncertainty principle(if I understand it correctly).

Originally posted by BuckWilder
reply to post by Astyanax

 

If you try to measure momentum, it's position that gets 'blurred out'.

So what does this mean with regards to debunking quantum consciousness?

How about - it might mean that the expectations or hopes of the experimenters moved the impact of the measurement.

A complete experiment in my opinion would have them measure the experimenters, and the equipment. And maybe another entangled photon to see what is happening to it.

Quantum Mechanics is made from a list of observable facts. That list of facts does not include what an electron or proton actually are. Are they charged clouds of varying shape and size or some sort of thing like an amoeba or a star?

The uncertainty principle has more to do with continuing on with blind spots than a rule about the conduct of nature.

reply to post by moebius

The thread title is incorrect/incomplete I think. The uncertainty principle is not violated.

Well, it is and it isn't.

The title of the paper we are discussing seems unambiguous: 'Violation of Heisenberg's Measurement-Disturbance Relationship by Weak Measurements'. There is, however, a complication.

Here is how Heisenberg stated the relationship (quoted in the paper; thanks to DrZrD for the link):

At the instant of time when the position is determined, that is, at the instant when the photon is scattered by the electron, the electron undergoes a discontinuous change in momentum. This change is the greater the smaller the wavelength of the light employed, i.e., the more exact the determination of the position.

However, as the authors of the paper point out, this isn't what is generally understood today as the Uncertainty Principle; we now speak of the intrinsic unknowability that exists in all physical systems. And you are right when you assert that it has not been violated.

What has been violated is Heisenberg's relationship between the degree of precision of a measurement and the resulting disturbance of the system being measured. It is shown that, using a series of 'weak' measurements, it is possible to obtain both an accurate measurement and a value for the resulting disturbance – momentum and position, in other words. We get to have our cake and eat it.

*

As already stated, I'm not keen on discussing mind-over-matter speculations arising from half-grasped ideas about quantum uncertainty (and I'm pretty sure you aren't, either, moebius). I like it when threads in the ATS science forum are about science, not metaphysics or mysticism.

However, it may be worth pointing out that what has been accomplished by these experimentalists is as follows: they observed the system as well as the change they caused by observing it. The subjectivity of observation, which is the plank on which most of these speculations is based, was thus eliminated; an objectively trustworthy picture of the system can after all be derived, independent of our observation of it.

As the authors of the paper conclude,

Using weak measurements to experimentally characterize a system before and after it interacts with a measurement apparatus, we have directly measured its precision and the disturbance. This has allowed us to measure a violation of Heisenberg's hypothesized MDR. Our work conclusively shows that, although correct for uncertainties in states, the form of Heisenberg's precision limit is incorrect if naively applied to measurement. Our work highlights an important fundamental difference between uncertainties in states and the limitations of measurement in quantum mechanics.

Objective reality, uncertain as it may be, is nonetheless conserved.

reply to post by Astyanax

As already stated, I'm not keen on discussing mind-over-matter speculations arising from half-grasped ideas about quantum uncertainty (and I'm pretty sure you aren't, either, moebius). I like it when threads in the ATS science forum are about science, not metaphysics or mysticism. However, it may be worth pointing out that what has been accomplished by these experimentalists is as follows: they observed the system as well as the change they caused by observing it. The subjectivity of observation, which is the plank on which most of these speculations is based, was thus eliminated; an objectively trustworthy picture of the system can after all be derived, independent of our observation of it.

It´s just your bias against quantum consciousness that made you jump to this conclusion. It has nothing to do with it.

The idea that the collapse of a wave function caused by knowing the path of a particle in a DS setup, pointing towards the role of consciousness, is not debunked or even remotely adressed by this experiment.

While there is a rigorously proven relationship about uncertainties intrinsic to any quantum system, often referred to as Heisenberg's Uncertainty Principle," Heisenberg originally formulated his ideas in terms of a relationship between the precision of a measurement and the disturbance it must create. Although this latter relationship is not rigorously proven, it is commonly believed (and taught) as an aspect of the broader uncertainty principle.

This is the interpretation of the Heisenberg principle that was violated in this new experiment,

The Heisenberg Uncertainty Principle is one of the cor-
nerstones of quantum mechanics. In his original paper
on the subject, Heisenberg wrote At the instant of time
when the position is determined, that is, at the instant
when the photon is scattered by the electron, the elec-
tron undergoes a discontinuous change in momentum.
This change is the greater the smaller the wavelength of
the light employed, i.e., the more exact the determina-
tion of the position

This is the broader interpretatation of the Heisenberg principle that would affect the theory of quantum consciousness, if violated, which it isn´t,

The modern version of the un- certainty principle proved in our textbooks today, how- ever, deals not with the precision of a measurement and the disturbance it introduces, but with the intrinsic uncertainty any quantum state must possess, regardless of what measurement (if any) is performed [2[4].

In conclusion, using weak measurements to experimentally characterize a system before and after it interacts with a measurement apparatus, we have directly measured its precision and the disturbance. This has allowed us to measure a violation of Heisenberg's hypothesized MDR. Our work conclusively shows that, although correct for uncertainties in states, the form of Heisenberg's precision limit is incorrect if naively applied to measurement.

The modern interpretation of Heisenberg principle, which is related to the notion of quantum consciousness, was not violated.

Objective reality, uncertain as it may be, is nonetheless conserved.

No it is not.

Our work highlights an important fundamental difference between uncertainties in states and the limita- tions of measurement in quantum mechanics.

This experiment doesn´t change the core of QP, reality is still subjective in Quantum physics, the only thing that changed are the limitations of measurement.

As already stated, I'm not keen on discussing mind-over-matter speculations arising from half-grasped ideas about quantum uncertainty (and I'm pretty sure you aren't, either, moebius). I like it when threads in the ATS science forum are about science, not metaphysics or mysticism.

As stated before, you are not keen on discussing anything that doesn´t fit your paradigm. Also, as shown before, you don´t even know what you are talking about exactly.

Incidentally, the BBC article contains an error:

No it doesn´t.

As most people interested in the subject know, what is 'blurred out' isn't always 'speed' (actually momentum); it depends on what's being measured.

Yes, either speed of momentum, BBC said this,

Heisenberg's uncertainty principle, as it came to be known later, started as an assertion that when trying to measure ONE ASPECT of a particle precisely, SAY its position, experimenters would necessarily "blur out" the precision in its speed.

It clearly suggested there are two variables, and named both of them, and it even made it clear that measuring one affected the other.

So what was the error?

Can I be horribly amused that you are arguing two states of understanding of subjective and objective nature of the universe in relationship to an experiment where conclusions are about the uncertainity of states and how to quantify them?

Please?

Do you feel violated?

Okay....I'll stop now.

reply to post by BuckWilder

Yes, well. I'm sure what you have written makes perfect sense to you.

Nice avatar, by the way. Much better than the one you had earlier.

reply to post by Aeons

No. Not unless feeling horribly violated is what pushes your button.

If such is the case, I suggest finding a like-minded spirit to push your button for you.

I'm afraid I'm not willing to perform that particular office.

Science thread and all that, you know.

reply to post by Astyanax


I rest my case.

reply to post by Vandettas


Interesting but changes nothing. Also as yet I haven't divined a use. If they were using the different crystals to measure photon orientation I would be yelling my encouragement. As we would have expanded the amount of information available.

Thanks for the post op – be keen to see any further developments. This however is using averages to estimate likely source. As such it is not a direct measurement of the particle and the waveform has not collapsed. Wonder how far we can push these measurements before it does so.