Uncertainty Inhererent in Nature

[IM Egdall]

Old explanations was that the act of measuring one parameter disturbs the measurement of the other conjugate -- like determining a particle's position disturbs its momentum. But this is a simplification. New test with neutrons verifies the uncertainty is there independent of the disturbance! Because a so-called particle also behaves like a wave, and this wave-like nature makes determining both its position and momentum to arbitrary accuracy impossible. Cool!

 

http://www.scienceda...20116095529.htm

Edited January 27, 2012 by IM Egdall

[swansont]

It's beyond a simplification, it's wrong. The uncertainty principle falls out of wave mechanics and is separate from the observer effect. Unfortunately, as with the Bohr atom, the history is taught and confused with the final formulation.

[DrRocket]

Old explanations was that the act of measuring one parameter disturbs the measurement of the other conjugate -- like determining a particle's position disturbs its momentum. But this is a simplification. New test with neutrons verifies the uncertainty is there independent of the disturbance! Because a so-called particle also behaves like a wave, and this wave-like nature makes determining both its position and momentum to arbitrary accuracy impossible. Cool!

 

http://www.scienceda...20116095529.htm

 

See swansont's blog for a discussion of bad science reporting.

 

See this article for what the researchers really said.

http://arxiv.org/abs/1201.1833

[IM Egdall]

Got it. Thanks swansont and DrRocket.

[Widdekind]

The uncertainty principle falls out of wave mechanics and is separate from the observer effect.

 

Does not the article agree with you ? Prof. Ozawa distinguishes "intrinsic uncertainty", from "observation uncertainty":

 

This was done by the Japanese physicist professor Masanao Ozawa in 2003, leading to a generalized uncertainty principle. His equations contain different "kinds of uncertainty": On the one hand the uncertainty which comes from the measurement, as it disturbs the particle (this is the uncertainty described in Heisenberg's thought experiment of the position-momentum-measurement), on the other hand the equations contain the fundamental quantum uncertainty, which is present in any quantum system, regardless of the measurement.

I understand, from the article, that "observation uncertainty" can be reduced arbitrarily; whilst "intrinsic uncertainty" is only minimizable, per HUP. If a quantum 'particle' is likened to a "school of fish", or "flock of birds", then the spatial extent of the "herd" represents intrinsic uncertainty, and is only minimizable; whereas observation uncertainty, would be like how much the "herd" is perturbed, by the presence, of the experimenter, e.g. the "flock of birds takes off in a new direction" (strong measurement) vs. "a few birds hop out of the way, whilst most of the flock keeps on feeding" (weak measurement).

[swansont]

Does not the article agree with you ? Prof. Ozawa distinguishes "intrinsic uncertainty", from "observation uncertainty"

 

No, it does not. The first paragraph implies that the observer effect is part of the HUP.

[Widdekind]

No, it does not. The first paragraph implies that the observer effect is part of the HUP.

 

I see no conflict, between what you said, and what Prof. Ozawa reportedly formulated, i.e. "there are two sources of uncertainty, one intrinsic to the 'particle'; and the other induced by the experimenter" ?

[swansont]

I see no conflict, between what you said, and what Prof. Ozawa reportedly formulated, i.e. "there are two sources of uncertainty, one intrinsic to the 'particle'; and the other induced by the experimenter" ?

 

That's because I am not disagreeing with what Prof Ozawa said. I am disagreeing with the way the article summarized it. Read the first paragraph of the article. It's wrong.

[Widdekind]

Until now, this has often been justified by the notion that every measurement necessarily has to disturb the quantum particle, which distorts the results of any further measurements. This, however, turns out to be an oversimplification, new research suggests.

I did not derive, from those words, any implication, that "observer induced uncertainty" is currently conceived to be the same, as "intrinsic Heisenberg uncertainty". I favor the popularization of important science, e.g. QM, given its immense potential power, e.g. for improving human life, on earth, so I'm partial to sites like SD.

[swansont]

Well, I do.

 

The "until now" implies that this is a new finding . It's not. That "this is an oversimplification" has been known for quite some time. The new research doesn't "suggest" this, it simply quantifies it, to some extent. That's not a small thing, mind you — it was probably a delicate experiment, and perhaps it was not possible to perform it until recently.

 

Science Daily generally reprints press releases, as in this case, so the fault here likely lies with the PAO who prepared the release. SD has a tendency to overstate how much of an article is actually due to their own work. In this instance they use their own byline and it's not until the very end of the page that you find the outside links, and they don't even go to the work in question.