EKM researches systems composed of many quantum mechanical particles, whose behaviour strongly influence one another. In physics, this is referred to as correlation. Through this, the entire system acquires new properties, as the particles act together collectively. “The whole is more than the sum of its parts,” explains Markus Heyl, professor for theoretical physics and member of EKM. We also say, “more is different.” We can use this to produce materials for innovative applications, as for example for new types of sensors or for quantum information technologies.

EKM was founded in the early 1990s at the University of Augsburg. The Federal Ministry of Education and Research (BMBF) and the Free State of Bavaria wanted to establish a centre of excellence in the field of quantum mechanical many-body physics. Since its establishment, it has been guided by an independent scientific advisory board. International experts provided a positive assessment of the centre at yesterday’s meeting. “We have acquired a prominent position in our field as well as in international comparison,” emphasised Heyl.

Processing quantum information

Quantum entanglement is an example of a special type of quantum mechanical correlation, which is best illustrated by example. Suppose two players simultaneously roll a dice with each cup of dice containing one dice each. Player A sees that they have rolled a six. This has no effect on player B's result: It is impossible to predict what number dice this player will roll. When it comes to the smallest particles, things are different. It is possible that both dice are interlocked. As soon as player A knows their result, they will also know player B’s result. “Correlation opens up a whole universe of innovative materials that are far from being exhausted,” explains Heyl.  

A specific example are strongly correlated materials that are suitable for storing quantum information. They are needed for new types of quantum computers that can solve certain problems thousands of times quicker than conventional computers. Quantum information is sensitive; it can be easily destroyed by external influences. It is therefore difficult to store quantum information for a long time. Correlated particle systems are therefore a possible solution. In such systems, information is stored in a “distributed” manner. As these storage units are correlated with one another, they mutually control one another, so they can prevent the loss of information. “However, quantum information processing is only one area in which the systems being researched are relevant,” emphasises Heyl. “We are conducting fundamental research, so our results are in principle of great importance to many areas.”

The members of EKM are the Chair for Theoretical Physics III (Prof. Heyl), the Chair for Experimental Physics V (Prof. István Kézsmárki), and the Chair of Experimental Physics VI (Prof. Philipp Gegenwart). The success of the centre is evident by a series of big projects in which it has played a substantial role over the last decade. These include the recent acquisition of a Transregio Collaborate Research Centre with the Technical University of Munich (TUM) and the Max Planck Institute for Solid State Research in Stuttgart. EKM is also a member of Munich Quantum Valley, an initiative of the Bavarian state government that aims to promote research in quantum physics in Germany.