Neutrons Can Bind to Nanoscale Atomic Clusters, Give Rise to New Types of Quantum Information Processing Devices

Compared to protons and electrons, neutrons do not possess any charge. They are held together inside the nucleus of an atom through the strong force at a very close range. It drops off so rapidly that it is negligible beyond 1/10,000 the size of an atom.

Neutrons are often used in neutron scattering experiments, where a bea, of neutrons is focused on a sample material. The neutral particles that bounce off the atoms of the material can be detected to reveal its dynamics and internal structure.

Discovery of Neutronic Molecules

No one has ever thought that neutrons can stick to quantum dots. In a wild twist, however, researchers from Massachusetts Institute of Technology (MIT) have figured out that these particles can actually bind to bigger structures.

In a new study, MIT experts conducted theoretical calculations and computational simulations done analytically in two different ways. The details of their experiment are discussed in the paper "μeV-Deep Neutron Bound States in Nanocrystals."

The researchers were surprised by their discovery since neutrons do not interact with electromagnetic forces. Among the four fundamental forces, gravity and the weak force are basically unimportant for materials.

Almost everything that involves neutrons is just electromagnetic interaction. In this case, the interaction is through very short-range strong interaction since the neutron does not have a charge. Its effectiveness is at 10 to -15 power, or quadrillionth of a meter.

According to MIT Professor Ju Li, this force that holds the nuclei of atoms together is tiny, but it is very intense. What is interesting is that the researchers got these many thousands of nuclei in the neutronic quantum dot with stabilized bound states, similar to Joseph John Thomson's plum pudding model of the atom.

The newly discovered state was dubbed by the scientists as an artificial "neutronic molecule". They are made of quantum dots, the minuscule crystalline particles composed of atoms whose precise size and form determine their characteristics more than their makeup.

In these nucleonic quantum dots, an individual neutron can be trapped by a nanocrystal with a size beyond the range of the nuclear force and display similar quantized energies. The neutronic quantum dots show potential in storing quantum information even if the energy jumps give quantum dots their colors.

Applications of Nucleonic Quantum Dots

The result of this study can be applied in determining the fundamental properties of materials at the quantum level and in exploring new types of quantum information processing devices. Professor Li believes that the artificial molecules can provide an interesting model system which can be used in studying quantum mechanical problems.

Neutrons have important roles in triggering fission and fusion reactions, but it has been difficult to control a single neutron. By changing the oscillation of quantum dots, scientists can shoot the neutron off in a particular direction.

Another possible application could be in imaging that uses neutron activation analysis. Neutron imaging complements X-ray imaging since the neutral particles are much more strongly interacting with light elements. While chemical imaging and spectroscopy do not provide a lot of information about isotopes, neutron-based methods can actually do so.

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