For the first time the spin of an electron has been measured. It is the best thing that can happen to quantum technologies

Spin is an intrinsic property of elementary particles, just like electric charge, derived from their angular moment of rotation. The first experimental evidence supporting its existence came in 1922 thanks to the experiments of the German physicists Otto Stern and Walther Gerlach, although scientists did not begin to understand the nature of this very important property of elementary particles until a few years later.

The reason why it is not easy to understand precisely what spin is is because it is a quantum phenomenon, so it is not entirely correct to describe it as a conventional rotational movement in space. Even so, the description that I have proposed in the previous paragraph is usually used for didactic purposes because it helps us to intuit without too much effort what we are talking about. In any case, the quantum nature of this property tells us something important: measuring it is difficult.

So much, in fact, that until now it had not been able to be done with precision. Fortunately, this wall has been torn down. And it is that a team of researchers made up of physicists from several Italian, German, British and American universities has managed to measure it for the first time. Of course, to achieve this they have been forced to use a synchrotron-type particle accelerator, a machine that keeps particles accelerated in a closed trajectory, as well as highly advanced techniques for analyzing the behavior of matter.

It is reasonable to foresee that it will have applications in quantum computing and beyond.

This statement by Domenico Di Sante, who is one of the researchers involved in this finding, express clearly what they have in hand: “The behavior of electrons in materials is conditioned by several quantum properties that determine the way in which they orbit in the matter of which they are a part. This phenomenon is similar to how the trajectory that light follows when travels through the universe is altered by the presence of stars, black holes, dark matter, or dark energy, which are capable of warping the space-time continuum.

The description that Di Sante proposes helps us to understand a little better why it is so difficult to measure the spin. In fact, leaving aside the more complex details of this experiment, they have achieved it by analyzing light absorption capacity that materials have depending on their polarization. They have used the synchrotron that we have talked about a little above, precisely, to generate light. However, the most important thing is the applications that this discovery can have.

Until now, it had not been possible to measure spin directly, which is precisely what these scientists have achieved, so the knowledge that this experiment has given them can make a difference in our understanding of the nature of matter. It is still not entirely clear what applications this milestone may have, but those responsible for the experiment hold that this knowledge can be used in disciplines as diverse as renewable energy, biomedicine or quantum computers.

In fact, if we stick to the latter, it is worth remembering that spin intervenes in the coding of the quantum state of a qubit, so it seems reasonable to accept that a deeper knowledge of this property of elementary particles can help scientists. quantum computing researchers design more robust qubits. Hopefully it will be like that. There is no doubt about one thing: the effort that is necessary to carry out experiments like this is worth it. After all, our scientific development depends on it.

Cover image: Xataka with Midjourney

rmation: Nature Physics

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