Resolution Of The Heisenberg Uncertainty Principle

bubblywatr writes: "A Caltech physics professor, Dr. Zewail, has apparently resolved the Heisenberg Uncertainty Principle (that the velocity and position of an electron cannot be determined simultaneously). He proposes in a recent issue of Nature(July 19: " The Fog that was not"), that one can solve, USING CLASSICAL PHYSICS (ie: f=ma), for the location and the position in space of a fundamental particle simultaneously by using FEMTOSECOND DATA COLLECTION (which can pick up atomic energy states), WHILE THE WAVEFORMS OF MATTER ARE IN COHERENCE (which minimizes the error of the femtosecond data because of the localizing effects of coherence). "

What does this mean? Femtosecond resolution apparently provides the localization needed to treat electrons as classical spheres in space, nearly following Newtonian physics. However, femtosecond chemistry has been around for years, so why hasn't this worked yet? Well, there is a great deal of error in gathering energy values, even when energies are collected at femtosecond intervals. This is due to freaky quantum physics i don't understand. But, as Zewail states, 'this freaky quantum error can be nearly eliminated if the matter is made coherent'. This means that the wavelike properties of matter are superimposed leading to the addition or destruction of waveforms. This is like the 'double slit experiment', in which regular light is shown through two slits, the waveforms either completely add or subtract, and what you see on the wall is a bunch of tiny spots of light at a defined point in space."

Comments

Astounding

[p3d0]

one can solve, USING CLASSICAL PHYSICS (ie: f=ma), for the location and the position in space of a fundamental particle simultaneously

Wow! Now, if only they could find both the velocity AND the speed.
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Re: Resolution Of TheHeisenberg Uncertainty Princi

[Fredbo]

But was he certain of that?

Re:God does not play dice.

[nekid_singularity]

I know that you are a pathetic troll, but I feel I should list the proof that Einstein's theory's have: The tiny precession in Mecurys orbit was explained perfectly by Special Relativity, the Gravitational lensing effect it predicted was observed, the time dilation has been proven in at least two ways, one that subatomic particles that should decay extremely rapidly when at rest last a lot longer when moving at close to the speed of light, and atomic clocks put on planes that rack up a great deal of miles run slow by exactley the amount einstien predicted. Finally, binary neutron stars slow down at a rate that is predicted by relativity from the energy loss of gravitational waves. The measured rate matches what the "dumb Jew" predicted to TWELVE or so decimal places. Its one of the single most succsessful theories in all Physics.

some clarifications

[esonik]

Zewail didn't "resolve" the Heisenberg Uncertainty Principle (HUR) (what does "resolve" mean in this context anyway ?). He has just pointed out why the HUR was not an obstace in femtochemistry:
a) it's a matter of numbers
b) coherence (which is needed for spatial localization) is not as instable as initially thought

for a) it's important to remember that he is talking about positions of NUCLEI which are quite
heavy objects (compared to e.g. electrons). Heavy objects have large momentum (p=mv) therefore a small uncertainty is not as disturbing as for light objects.

Now some comments on Hemos' text/questions:

Femtosecond resolution apparently provides the localization needed to treat electrons as classical spheres in space, nearly following Newtonian physics.

No, he is talking about "atomic motion", i.e. about nuclei. See above.

However, femtosecond chemistry has been around for years, so why hasn't this worked yet?

It has worked. The article is just a summary/explanation of why it has worked.

Well, there is a great deal of error in gathering energy values, even when energies are collected at femtosecond intervals. This is due to freaky quantum physics i don't understand.

The error is given by the HUR: Delta(E) >= hbar/(2*Delta(t)). The shorter you look, the larger the uncertainty. However, it turned out that the timescale of several ten femtoseconds is still large enough to have sufficient energy resolution.

This is like the 'double slit experiment', in which regular light is shown through two slits, the waveforms either completely add or subtract, and what you see on the wall is a bunch of tiny spots of light at a defined point in space.

No. The double slit experiment doesn't work with regular light, you need *coherent* light (e.g. a Laser). That's exactly the point Zewail makes: if they had used incoherent states (or if the coherency was destroyed fast) they would not have observed localized atoms ( = your "tiny spots of light")

Comment+Clarification

[bubblywatr]

Indeed some clarification is in need:

First, Zewail apparently has been pushing these ideas for some time, and Nature just gave him the opportunity to get it publicized a little. This is theory, people aren't going to go simultaneously calculate position and velocity of fundamental particles this afternoon, but he theorizes that with these two conditions met, such a characterization could be possible. As far as I understand, that is all he is claiming.

Second, when I said "he proposes in a recent issue of Nature...that one can solve, USING CLASSICAL PHYSICS (ie: f=ma)..." the (f=ma) is an EXAMPLE of what classical Newtonian physics is. I am not sure how that got misunderstood, but I apologize for my ambiguity. Perhaps it would have been better to simply quote Zewail as I will do now: "But if these waves are added up coherently with well-defined phases, the probability distribution becomes localized in space. The resultant wave packet and its associated de Broglie wavelength has the essential character of a classical particle: a trajectory in space and time with a well-defined (group) velocity and position - a moving classical marble but at atomic scale!" (Nature 2001, 412, p.279).

Even if my explanation was convoluted, I simply hope to get across Zewail's main idea: that quantum uncertainty is no longer an obstacle, and therefore openening the theoretical possibility for the resolution of HUP.