What is a quantum material

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In common materials, electrons, which are responsible for transporting electricity, have to find their way through evenly distributed obstacles in the solid. In the topological quantum materials, on the other hand, particles can only move on certain more or less twisted paths (which contain a twist) and, in accordance with the laws of quantum physics, also behave like particles and waves at the same time.

There is one central property that can fully describe the topology, i.e. the quantum twist of these materials: the "Berry curvature", named after the English physicist Michael Berry, who created the basic concept for it back in the 1980s. The team around Prof. Dr. Klaus Sengstock and Dr. Christof Weitenberg from the Institute for Laser Physics at the University of Hamburg was now able to completely measure the Berry curvature in a quantum material for the first time.

The physicists deliberately used an artificial quantum material that is used intensively around the world today: atomic clouds - so-called “ultra-cold quantum gases” - in an artificial solid, formed from laser light. After the atoms, which took on the role of electrons in solids in these experiments, had been introduced into the artificial material that contained the topology to be investigated, this topology could be measured very precisely with the help of further lasers.

Vision quantum computer

Dr. Weitenberg, who supervised the experiments, emphasizes: "We were already able to determine the topology of an artificial material in these first experiments, and that is just the beginning, we are all very enthusiastic about the possibilities of this new method." Prof. Sengstock adds: " Novel quantum materials will play an important role in the foreseeable quantum technologies in the near future; Quantum computers are particularly visionary and can only be realized through new concepts. "Materials with a certain twist can probably make important contributions to this:" It is particularly exciting to research in this area because the research field of these new quantum materials is only just beginning. much has not yet been researched, ”says Prof. Sengstock.

The article in Science, Vol. 352, Issue 6289, pp. 1091-1094 (2016):


DOI: 10.1126 / science.aad4568