[sjastro]

Originally Posted by CraigS

Y'know Alex .. that's a very interesting question. I don't know myself.

A few articles have appeared lately that have thrown me when it comes to this question … here's a thread about 'The Shape of an Electron' .. one of the articles in the thread says ..


… so how is it that they can measure accurately the shape of an electron, at this degree of precision, and yet the Heisenberg Uncertainty Principle is frequently cited as a reason why such precision cannot be achieved ? Clearly, it can be achieved ! What purpose does the Uncertain Principle serve in this case ? Is it as relevant as it once was ?

They not measuring a shape. What they are trying to do is measure an electron's dipole moment. The more distorted the shape, the greater the dipole moment. If an electron is perfectly spherical the electron dipole moment is zero.

And I've been pondering another one … Startling thermal energy behavior revealed by neutron scattering.
.. in this one, they have found that the vibrations of atoms in a crystal lattice in thermal equilibrium, (the vibrations are indicative of thermal energy), self-organise into discrete packets, called intrinsic localized modes (ILMs) that break the symmetry of the crystal. They found that the ILMs self-organised according to a regular pattern. Whilst this is indicative of a chaotic phenomenon forming fractal patterns of both regularity and irregularity, (which is no great surprise to yours truly), my question is: How do they measure this kind of stuff when QM is telling us that its all a matter of probability ? This particular test made use of neutron scattering to collect the vibration data of atoms trapped within the lattice structures.[

Hmmm if the size of the crystal is greater than it's Compton wavelength, then the measurements are entirely predictable and not quantum mechanical.

Another recent one is: Quantum physics first: Researchers observe single photons in two-slit interferometer experiment.
In this, they have developed a way to make momentum and distance measurements on photons which may ultimately lead to tracing their paths backwards to the specific slit they went through.

Interestingly enough the reasercher's themselves are not claiming to violate the uncertainty principle.

Steinberg stresses that his group's work does not challenge the uncertainty principle, pointing out that the results could, in principle, be predicted with standard quantum mechanics. But, he says, "it is not necessary to interpret the uncertainty principle as rigidly as we are often taught to do", arguing that other interpretations of quantum mechanics, such as the pilot-wave theory, might "help us to think in new ways".

What the experiment does challenge is the Copenhagen interpretation of QM, where a wavefunction collapses when a measurement is performed.

Regards

Steven