Quantum Transport and Quantum Technology

The theorist Prof. Dr. Wolfgang Belzig reported on 02 December 2021 in his lecture "Quantum Transport and Quantum Technology: Squeezed Vacuum and Synthetic Topology" about his field of research and recent discoveries of his research group.

Quantum mechanics is the most successful physical theory of all time. Countless technologies that are taken for granted today have their origin in quantum effects - for example semiconductors, lasers or superconductors. Often, however, quantum effects appear very abstract, inconceivable and only indirectly visible in experiments. Making quantum physics tangible and applicable is a central concern of our theoretical research. In the talk, I will use two exemplary phenomena to show how our surprising theoretical predictions enable novel applications in quantum technology.

The first part is about the vacuum state of a quantum field, for example the spins of a magnetic material. We were able to show that the ground state of spin waves is in general a quantum mechanically highly entangled state, which thus represents a unique quantum battery for quantum technology. One of the experimentally leading groups worldwide (in Konstanz!) is currently trying to prove these quantum correlations.

In the second part, I show how superconducting nanostructures can realize quantum systems with synthetic dimensions and thus a variety of exotic - previously unproven - quantum effects. These include topologically protected quantum bits, non-Abelian Berry phases, and the tensor monopoles known from string theory. The potential for applications in quantum information, quantum sensing, and quantum simulation can hardly be estimated due to the still very recent findings. The prospect of creating an almost unlimited number of topologically protected synthetic dimensions is extremely promising.