Researchers in Germany have split the unsplittable and separated a single atom into two halves, pulling it apart and putting it back together again.
The laws of quantum mechanics allow objects to exist in several states simultaneously and researchers from the University of Bonn were able to keep a single atom concurrently in two places that were more than ten micrometres apart, before putting the atom back together. They hope to build quantum mechanics bridges by letting the atom touch nearby atoms when pulled apart so it works like a bridge span between two pillars.
Fragile quantum effects can only occur at low temperatures and with careful handling – one method involves cooling a caesium atom using lasers to a tenth of a million above absolute zero. A second laser holds the atom and is key to splitting it in two. Depending on the spin of the atom, it can be moved to the left or right by the laser like on a conveyer.
“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,” said Andreas Steffen, lead author of the study published in Proceedings of the National Academy of Sciences.
However, the split cannot be seen directly, but it can be proved successfully by putting the atom back together. An interferometer can be built from individual atoms that could, for example, be used to measure external impacts precisely. What is visible are differences between the magnetic fields of the two positions or accelerations since they become imprinted in the quantum mechanical state of the atom.
The scientists also wanted to simulate complex quantum systems, which might consist of modelling the movements of electrons in solid bodies. However, 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.
And this is where the significance lies – since the two halves are put back together, they can make contact with adjacent atoms and share it, meaning a small network of atoms can be used to simulate and control real systems.