New type of quantum magnetic behavior with ultra-cold atoms

MIT and Harvard researchers have studied how elementary units of magnetism, called spins (the black arrows), move around and interact with other spins, in a chain of single atoms (the colored spheres). The background shows a real image of the spins, revealing a high contrast periodic modulation of the blue (spin up) atoms. Credit: Courtesy of the researchers

Researchers from MIT and Harvard University reveal how magnetic forces at the quantum, atomic scale affect how atoms orient their spins.

In experiments with ultra-cold lithium atoms, they observed different ways in which the spins of the atoms evolve. The spinning atoms return to an equilibrium orientation in a way that depends on the magnetic forces between individual atoms.

The researchers found that these behaviors, which had not been observed until now, could be described mathematically by the Heisenberg model, a set of equations commonly used to predict magnetic behavior. Their results address the fundamental nature of magnetism, revealing a diversity of behavior in one of the simplest magnetic materials.

This improved understanding of magnetism may help engineers design “spintronic” devices, which transmit, process, and store information using the spin of quantum particles rather than the flow of electrons. (MIT)

The paper has been published in Nature.

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