The shape of an electron determined for the first time

The electron, an elementary particle that constitutes one the fundamental parts of an atom have been well studied and researched over the last two centuries. Physicists know a lot of its properties. But until then, scientists have struggled to determine one of its most characteristics: its shape.

Researchers at the University of Basel (Switzerland) have developed a method for determining the geometry of electrons confined in an artificial atom. A first that could pave the way for the development of future quantum computers.

An artificial atom is a quantum box in which it is possible to confine electrons by means of electric fields. The electrons behave in the same way as if they were linked to an atom. The electrons continue to move, but in a space about 1,000 times larger than a classical atom. And the theory is that researchers can locate them with a certain probability depending on their wave function.

An electron is trapped in a quantum box formed in a two-dimensional gas between two semiconductor layers. The electron presents different probabilities of presence in space, corresponding to a wave function (red ellipses).

Thanks to spectroscopic measurements, physicists at the University of Basel were able to determine the energy levels in such an artificial atom. They studied the behavior of these energy levels subjected to magnetic fields of different intensities and orientations. And they were able, based on their theoretical model, to determine the probability density of an electron’s presence – and therefore its wave function – with a precision less than one nanometer.

Since the stability of the spin of an electron, as well as the entanglement of the spins of several electrons, depend, among other things, on the geometry of the electrons, the researchers should now be able to better understand the phenomena involved. They should be able to better control the spins of electrons. The same ones that could be the smallest information units of a future quantum computer, the qubits.

Carl Frantz

Polyglot, humanitarian, Carl was born in Germany but raised in the USA. He writes mostly on tech, science and culture.