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Scientists Measure Magnetic Interaction Between Two Bound Electrons
An anonymous reader writes In a paper published in Nature (abstract), scientists report successfully measuring the magnetic interaction of two bound electrons of two different strontium (Sr) ions. The two ions were suspended in a quadrupole ion trap (a.k.a. a Paul trap), and the effects of ambient magnetic noise were mitigated by 'restricting the spin evolution [of the electrons] to a decoherence-free subspace that is immune to collective magnetic field noise.' The scientists measured the magnetic interaction of the two electrons as a function of distance and found that the force acting between the two was inversely dependant on the cubed distance between the electrons, consistent with Newton's inverse-cube law.
What's your point?
There is a lot of stuff not everyone knows.
Should we only study things everyone already knows?
Should news only be reported if everyone already knows?
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Newton's inverse-cube law is still valid. That's good news.
Bah, this is dipole-dipole interaction, of course it goes like 1/r^3. Had it not, we'd have had to defenestrate at least some of Maxwell's equations and those are just too well tested (well, magnetic multipole corrections could have been in question too, but that's been tested a lot as well). The experimental setup is the interesting part though.
From ingress "the force acting between the two was inversely dependant on the cubed distance between the electrons" This should not be understood as inverse cube force between the electrons. From article: "By varying the separation between the two ions, they were able to measure the strength of the magnetic interaction as a function of distance – confirming the expected inverse-cubic (1/d3) dependence of the interaction."
It is the strength of the interaction that is found to be inverse cubic. The strength of magnetic force is inverse quadratic. If somebody found evidence of an inverse cubic force then this would be evidence of higher-spatial dimensions and very unexpected indeed. There has been speculation that gravity might be higher-dimensional at very small scales, but I have never heard anyone make this claim of of electromagnetic forces. The cross-product nature of the electric/magnetic interaction makes these forces a true child of an 3 dimensional space.
Gravity is also inversely proportional.... we are so close to figuring out how everything really works, but will probably not happen in our life times :(
Neat! Newtonian physics at the atomic level. Does anyone know if the inverse square law has been tested in other ways at this scale? Or other Newtonian laws?
The phenomenon was known, a hypothesis existed to predict the results, and a test was devised to confirm the hypothesis. One critique, the article only mentions one Strontium ion separation, 10um. I would suggest that the test be repeated at multiple separations, and then determine if the data correlates with the predictions.
Most (if not all) of these findings are derivable from a well forgotten completed theoretical and experimental work on hydrodynamics by Prof. C. A. Bjerknes extended his son Vilhem Bjerknes. The problem is though that in the contemporary research all these "old" theories are not even looked, not to mentioned considered as viable, for their base on the idea about Ether, that somehow is crippling back in to the mainstream science ( willingly or not) although in somehow different form ( black energy or matter, or whatever you name it).
One major point in their theory is the assumption of the existence of the so called Maxwellian stress as as static stress of the underlying physical substrata. As Maxwell noted that he is not clear about this and makes some assumptions, that this stress can only be due to stress of anisotropic type, idea that the following researchers and theoreticians will move to investigate this, (THE) fundamental problem of the theory of electrical sciences. Somehow, or may be "of course" none of the followers worked on this (hard) problem, till C. A. Bjerknes developed his investigations ( and much more) and showed theoretically and practically, vis simple hydrodynamic experiments, that even "a simple isotropic stress can produce actions of the type which Maxwell supposed explicable only as the effect of a stress of the anisotropic type" - "On the Maxwell Stress Theory", V. Bjerknes, Philosophical Magazine p.491, 1905.
This is not stuff everyone knows.
If Slashdot only told me things I already knew, I wouldn't come here. Duh.
There was enough there to understand the gist of it
Perfect. That's exactly what I want from a Slashdot summary. Then, if I want to read further, I can.
systemd is Roko's Basilisk.
I remember Newton's inverse square law, but magnetic dipoles were more than two centuries after his time.
A Shadeless room is a brighter room.
'restricting the spin evolution [of the electrons] to a decoherence-free subspace that is immune to collective magnetic field noise.'
I bet they had to hit them with a inverse tachyon beam from the main deflector dish to do that.
The big leap hear was observing the interaction of *only* 2 spins, not the physics. Just to be clear, this study has confirmed that standard spin physics work on the atomic scale. Confirming these basic laws for a system of two atoms is important because it can expose holes in our understanding of physics that came from only observing an ensemble of spins and not single spin states. Just a few notes: Derivations of quantum mechanical interactions come from basic formulas of classical mechanics, but strictly speak the physics in this paper are *NOT* Newtonian. They are talking about the energy of the interaction, not the force. For two electron dipoles interacting in space, the basic formulation come from F = (q1*q2)/(d^4). Because energy is force x distance: E = F*d = (q1*q2)/d^-3. This observation *is* expected since these physics govern basic magnetic resonance principles. The leap here comes from the fact that magnetic resonance experiments deal with LOTS of atoms, not two.
It is a verification of something we were unable to verify before. This shows that newton got it right, which is excellent given the level of technology we had at the time he derived his formulas. Einstein gets all the credit but I think newton may have been the true genius.
How do you rule out confirmation bias when you are observing something so fiddly? See also http://science.slashdot.org/story/14/06/22/1219221/big-bang-breakthrough-team-back-pedals-on-major-result
Probably about equal, but Einstein couldn't have done his work without the foundations built by Newton. Of course, Newton.... Kepler... Tyco Brahe... "and so proceed ad infinitum"
I think we've pushed this "anyone can grow up to be president" thing too far.
The problem for me is that while I can just about convince myself that I have a mental picture of the electrons in a wire being attracted to the nuclei in a parallel wire due to their relative motion making them appear to be more densely packed because of Lorentz contraction. I can't picture what relativistic affects might come into play between two electrons, or even, say, two parallel beams of electrons, that would be ascribed to a magnetic force. If anyone can point me toward an internet resource that provides a simple explanation I'd be grateful.
Nullius in verba