quantum mechanics
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The magnetic properties of two highly charged neon in an ion trap have been measured using a newly developed technique. This difference can be compared with equally precise theoretical calculations of it. The standard model of physics has been confirmed by the agreement of the results.

Some of the most important building blocks of the matter are electrons. The negative charge and spin are two very distinct properties of them. Each electron has a magnetic moment that's similar to a compass needle. The g-factor can be used to predict the strength of themagnetic moment. One of the most precise matches of theory and experiment in physics has been found with this calculation. The magnetic moment of the electron is unaffected by other influences but instead is bound to an atomic nucleus. QED can be used to calculate the slight changes of the g-factor. This theory can be tested with high-precision measurement.

The group leader reports that they have succeeded in investigating the QED predictions with unprecedented resolution. We looked at the difference in the g-factor for two of the highly charged neon ion's that only have one electron. The QED effects are enhanced by 10 times the nuclear charge of these. When the nuclear charge is the same, there is no difference in the number of neutrons in the nucleus. There were 20 Ne 9+ and 22 Ne 9+ with 10 and 12 neutrons.

A Penning trap is used in the ALPHATRAP experiment to store single ion in a strong magnetic field. The purpose of the measurement is to find out how much energy is needed to flip the compass needle. The exact frequencies of the microwaves needed for this are looked for. The exact value of the magnetic field is what makes this Frequency different. The researchers use the motion of ion in the Penning trap to figure out what's going on.

Despite the very good temporal stability of the superconducting magnet used here, unavoidable tiny fluctuations of the magnetic field limit previous measurement to about 11 digits of accuracy.

Fabian Heie, Postdoc at the ALPHATRAP experiment, says that in such a motion, the two ion always move in opposite directions.

The fluctuations of the magnetic field have the same effect on both isotopes as they do on each other. The researchers were able to determine the difference of the g-factors of both isotopes with record accuracy to 13 digits, an improvement by a factor of 100 compared to previous measurement, and thus the most accurate comparison of two g-factors in the world. If the researchers had measured Germany's highest mountain, the Zugspitze, with such precision, they would be able to identify individual atoms on the summit by the height of the mountain.

The calculations were done in the same way in the department. The electron interacts with the atomic nucleus via the exchange of photons, as predicted by QED, according to group leader Zoltn Harman. This has been solved and successfully tested for the first time. If the QED results are known, the study will allow the nuclear radii of the isotopes to be determined more precisely than before.

The strength of the interaction of the ion with dark matter is one example of a new physics that can be constrained.

The method presented here could allow for a number of novel and exciting experiments, such as the direct comparison of matter and antimatter or the ultra-precise determination of fundamental constants.

More information: Tim Sailer et al, Measurement of the bound-electron g-factor difference in coupled ions, Nature (2022). DOI: 10.1038/s41586-022-04807-w Journal information: Nature