Physicists split an atom using quantum mechanics precision

Physicists split an atom using quantum mechanics precision

Researchers from the University of Bonn have just shown how a single atom can be split into its two halves, pulled apart and put back together again. While the word "atom" literally means "indivisible," the laws of quantum mechanics allow dividing atoms - similarly to light rays - and reuniting them. The researchers want to build quantum mechanics bridges by letting the atom touch adjacent atoms while it is being pulled apart so that it works like a bridge span between two pillars. The results have just been published in the journal Proceedings of the National Academy of Sciences.

Dividing ? What sounds like and radioactivity is, however, a precision process using quantum mechanics. The laws of allow objects to exist in several states simultaneously. This is what the so-called double-slit experiment is based on, where a particle can go through two slits at the same time. The Bonn scientists working with Prof. Dr. Dieter Meschede from the Institute for Applied Physics of the University of Bonn succeeded in keeping a single atom simultaneously in two places that were more than ten micrometers, or one hundredth of a millimeter, apart. This is an enormous distance for an atom. Afterwards, the atom was put back together undamaged.

The fragile can only occur at the lowest temperatures and with careful handling. One method is cooling a enormously using lasers – to a temperature of a tenth of a million above absolute zero – and then holding it with another laser. This laser beam is key to splitting the atom. It works because atoms have a spin that can go in two directions. Depending on the direction, the atom can be moved to the right or the left by the like on a conveyor. Key is that the atom's spin can be in both directions simultaneously. So, if the atom is moved to the right and left at the same time, it will split. "The atom has kind of a split personality, half of it is to the right, and half to the left, and yet, it is still whole," explained Andreas Steffen, the publication's lead author.

But you cannot see the split directly; if you shine a light on the atom to take a picture, the split will collapse immediately. The atom can then be seen in several images; sometimes on the left, sometimes on the right - but never in both places. And yet, the split can be proved successfully by putting the atom back together. Thus an interferometer can be built from individual atoms that can, e.g., be used to measure external impacts precisely. Here, the atoms are split, moved apart and joined again. What will become visible, e.g., are differences between the magnetic fields of the two positions or accelerations since they become imprinted in the quantum mechanical state of the atom. This principle has already been used to very precisely survey forces such as the earth's acceleration.

The Bonn scientists, however, are looking for something else: simulating complex quantum systems. Many physicists have been hoping for a long time to be able to simulate so-called topological isolators or plant photo¬synthesis – phenomena that are hard to capture with modern super computers – using small quantum systems. The first steps on the way to such simulators could consist of modeling the movement of electrons in solid bodies, thus gaining insights for innovative electronic devices. Examples for this are Dirac motion of electrons in a single graph-layer or the emergence of artificial molecules from interacting particles. But for this purpose, individual atoms would not only have to be well controlled, but also linked according to quantum mechanical laws since where the crux of the matter lies is exactly in a structure made up from many quantum objects.

"For us, an atom is a well-controlled and oiled cog," said Dr. Andrea Alberti, the team lead for the Bonn experiment. "You can build a calculator with remarkable performance using these cogs, but in order for it to work, they have to engage." This is where the actual significance of splitting atoms lies: Because the two halves are put back together again, they can make contact with adjacent atoms to their left and right and then share it. This allows a small network of atoms to form that can be used – like in the memory of a computer – to simulate and control real systems, which would make their secrets more accessible. The scientists believe that the entire potential of controlling individual atoms this precisely will become apparent over time.

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More information: A digital atom interferometer with single particle control on a discretized space-time geometry, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1204285109
Provided by University of Bonn
Citation: Physicists split an atom using quantum mechanics precision (2012, June 5) retrieved 14 October 2019 from
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Jun 05, 2012
Very misleading title. This is not splitting an atom, it is just superposition. Still impressive though.

Jun 05, 2012
IMO it's not splitting of atoms, but the separation of de-Broglie wave created around them by their motion (sorta wake wave, which is formed in elastic vacuum foam around all particles in motion). Analogously, during double slit experiment every particle physically passes trough one slit only, only its deBroglie wave is so large, it can interfere with both slits at the same moment.

Jun 05, 2012
Very misleading title. This is not splitting an atom, it is just superposition. Still impressive though.

At ten microns distance it's really hard to imagine that the atom hasn't split. But, of course, you are right: we're talking superposition here.
Still: Such a large distance is really freaky.

Jun 05, 2012
If the consideration of the interaction of matter was based on the Wave functions of particles, rather than the Bohr 'particle' model,
Physics would move apace much faster.
That the Graviton has fallen by the wayside, and that the Higg's particle will soon follow, should spur us along the path of Wave Mechanics to the realization that Gravity and other forces are the results of wave refraction.

Jun 05, 2012
The wave mechanics alone don't work, since they can't deal with energy quanta (which are observed). That's why wave mechanics theory was dropped in the late 1920s (and the Bohr model some time before that).

If we hadn't moved on to quantum mechanics from these two models then we'd still be stuck scratching our heads about most things in the microscopic worlds.

Jun 05, 2012
What happens to an electron spinning around an atom if the atom is split into two ? Would it still orbit half the nucleus or what?

I don't know much about this so my question probably sounds stupid :P

Jun 05, 2012
There are no stupid questions... only stupid answers (see sockpuppets above on quantum foam theory)

Technically the electron doesn't "orbit" anything (and isn't really a concrete 'thing' in a classic sense). So stop imagining a little particle orbiting round a central nucleus. This analogy doesn't work any more.

Think of it's orbit as more of a zone where the electron has a certain high probability of existing at any given time. Most of the time it appears and disappears within this zone, sometimes it's elsewhere.

I would imagine that the superposition of the atom would also require the superposition of the electron and it's orbital... i.e. the 'space' in which the electron is likely to be found would also be found to both the left and the right.
However, I'm sure someone here who is much more knowledgeable will provide specifics.

Jun 06, 2012
So would there be two different zones for one electron to possibly be or could one possibly be on both halves affectively having two electrons.... unless the electron halves too to keep the energy balanced :$

Jun 06, 2012
Electrons have a charge and therefore you will not have 'two electrons' (otherwise there would be a surplus of charge suddenly appearing in the system). Electrons also have mass. Having 'two electrons' would double the mass (this would also go for the nucleus, BTW). Neither of these effects are observed.

It's hard but you have to imagine stuff not as being small, hard, points/objects but as probability distributions of an entity (whatever that is) over a volume. The probability distribution usualy peaks in a very small volume (i.e. your 'entity' is prtty localized and can be thought of as being 'there').

With experiments like these the probability distribution is widened to the point where the 'there' is stretched over a large volume. The entity isn't in one place within that distribution but everywhere within that distribution at once (only when you measure it does this distribution collapse to one point)

How does this (supposedly) "split" atom react to an external magnetic field? Much of the explanation on the split/superposition is still not clarified, I must say.

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