Researchers from the University of Basel have demonstrated, for the first time, what an individual electron looks like in an artificial atom. Thanks to new techniques, it is now possible to show the probability of an electron being present in a given space.
The method will enable improved control of electron spins and this insight may be useful for the development of future-state quantum computers. This is because the spin of an electron is related to the smallest information unit (qubit) of a quantum computer.
Understanding more fully the shape of electrons can help to advance quantum computing, since altering and varying the spin of an electron, or coupling electrons together, can assist with tighter quantum control. Achieving better control has proved challenging, up until now, due to scientists not completely understanding the geometry of the electron. The new research into electron geometry could pave the way towards achieving the level of electron spin control necessary to push quantum computing forwards.
An electron is a subatomic particle which has a negative electric charge. The quantum mechanical properties of the electron include an intrinsic angular momentum and having the relationship whereby no two electrons can occupy the same quantum state. Electrons are linked to several physical phenomena, like electricity, magnetism, chemistry and thermal conductivity.
To assess the geometry of electrons, the researchers used a quantum dot. Quantum dots are tiny particles or nanocrystals of a semiconducting material with diameters in the range of 2-10 nanometers.
To derive at the model, the researchers deployed spectroscopic measurements to assess the energy levels in a quantum dot and used the collected data to study the behavior of varying levels in magnetic fields. The readings enabled them to determine the electron’s density and its wave function down to the sub-nanometer scale.
This produced a map the shape and orientation of the electron. As lead researcher Daniel Loss states: “To put it simply, we can use this method to show what an electron looks like for the first time.”
The new method is outlined in the journal Physical Review Letters (“Spectroscopy of Quantum Dot Orbitals with In-Plane Magnetic Fields”). The theory underpinning the method and the electron structure is detailed in a companion article, published in the journal Physical Review B, titled “Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot.”
