The Geometry of An Electron Determined For the First Time

Physicists at the Swiss Nanoscience Institute at the University of Basel have now developed a method by which they can spatially determine the geometry of electrons in quantum dots. Space Daily reports: A quantum dot is a potential trap which allows to confine free electrons in an area which is about 1000 times larger than a natural atom. Because the trapped electrons behave similar to electrons bound to an atom, quantum dots are also known as 'artificial atoms.' The electron is held in the quantum dot by electric fields. However, it moves within the space and, with different probabilities corresponding to a wave function, remains in certain locations within its confinement.

The scientists use spectroscopic measurements to determine the energy levels in the quantum dot and study the behavior of these levels in magnetic fields of varying strength and orientation. Based on their theoretical model, it is possible to determine the electron's probability density and thus its wave function with a precision on the sub-nanometer scale. 'We are able to not only map the shape and orientation of the electron, but also control the wave function according to the configuration of the applied electric fields. This gives us the opportunity to optimize control of the spins in a very targeted manner,' says one of the researchers. The spatial orientation of the electrons also plays a role in the entanglement of several spins. Similarly to the binding of two atoms to a molecule, the wave functions of two electrons must lie on one plane for successful entanglement. With the aid of the developed method, numerous earlier studies can be better understood and the performance of spin qubits can be further optimized in the future.
The research has been published in two papers in Physical Review Letters and Physical Review B.

Read more of this story at Slashdot.