This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers at Delft University of Technology (the Netherlands) have succeeded in controlling the magnetism in the nucleus of a single atom with radio waves. This came as a surprise: until now, physicists believed that this nuclear spin could not be manipulated directly.
The discovery could open up new possibilities for storing and reading quantum information. The research is published in the journal Nature Communications. In metals such as iron and nickel, every atom is slightly magnetic.
But inside the atom, different magnetic "compass needles," known in quantum mechanics as spins, are also at work. "By far the strongest magnetism comes from the electrons," says lead researcher Sander Otte. "But in some atoms, the nucleus also carries a spin.
That spin is much weaker, but it is also much better shielded from the outside world." Otte's group studies spins using a converted scanning tunneling microscope. This enables electrical signals to be directed with extreme precision at a single atom. In the past, the researchers mainly focused on the electron spin, which is the easiest to read out.
The nuclear spin appeared only indirectly, through the so-called hyperfine interaction. This causes the spins of the nucleus and the electron to become slightly entangled. In their latest experiment, main author Hester Vennema and her colleagues sent two different signals to an atom simultaneously: one targeting the electron and one targeting the nucleus.
This allowed them to study the influence of each signal independently. To their surprise, they found that they could flip the nuclear spin even when the two spins were largely disentangled. That result came unexpectedly.
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