New scientific breakthrough: quantum geometry measured for the first time

Physicists at the Massachusetts Institute of Technology (MIT) in the US, in collaboration with colleagues, have for the first time measured at the quantum level the geometry, or shape, of electrons in solid bodies. Although scientists have long been able to measure the energies and velocities of electrons in crystalline materials, the quantum geometry of these systems has remained theoretical and, in some cases, completely obscure until now.

A universal approach

This new work by scientists opens up new possibilities for understanding and manipulating the quantum properties of materials.

"We have essentially developed a blueprint for obtaining completely new information that was previously unavailable," said Riccardo Cominas, a scientist and leader of the study. 

The method discovered by the researchers, which allowed them to calculate quantum geometry, can be applied to any quantum material, not just the one they worked with.

The strange quantum world

In quantum physics, an electron can be both a point in space and a wave-shaped object. This is described by a wave function - it can be imagined as a surface in three-dimensional space.

Wave functions can be simple, like a ball, or complex, like a Mobius strip. 

It is the latter that make up many of the quantum materials that may have applications in quantum computers or advanced technologies.

Until now, the quantum geometry of these functions has only been possible at a theoretical level. But MIT researchers using the ARPES method have been able to measure it in kagome metal, a quantum material whose properties have previously surprised researchers.

Close cooperation

According to Min-gi Kang, another of the study's authors, the ability to accurately measure the quantum geometry of materials is due to a strong collaboration between theorists and experimentalists.

The COVID-19 pandemic was also a factor. While in South Korea, Mr Kang forged closer links with local theorists, which led to a successful collaborative effort to unravel the mystery of quantum geometry.

Meanwhile, Cominas travelled to Italy during the pandemic to carry out quantum experiments at the Elettra laboratory. When he arrived, the laboratory was just opening. 

However, Mr Kang was unable to join the Italian lab due to a positive COVID test, so Mr Cominas stayed behind and carried out the experiments himself with the help of local scientists.