At a glance FIG. 3. Developing theoretical findings towards experimentally relevant prediction is a key objective of the TOPOLECTRICS project. We have predicted the material SrPtAs to exhibit a topologically non-trivial superconducting state. Shown is the Fermi surface structure, featuring Majorana-Weyl nodes of the superconducting order parameter. In the projected (010) surface Brillouin zone, Fermi arcs of chiral Majorana fermions are found. Further details can be found in Fischer et al., Phys. Rev. B 89, 020509(R); 90, 099902(E) (2014).
Superconducting materials This research may seem theoretical in nature, but Professor Thomale’s research also holds practical implications, notably in terms of energy sustainability. One major area of Professor Thomale’s research is superconductivity, a phenomenon where electrical resistance disappears at a critical temperature. “The study of topological states of matter, as we think of them now, started in the ‘80s with Klaus von Klitzing, while superconductivity was discovered by Heike Kammerlingh Onnes in 1911, so the field is over 100 years old,” he explains. “But these fields are linked, and we want to contribute to strengthening these links in our project.” A unified theoretical language would link this field in a much more rigorous way to other disciplines in physics, giving researchers a clearer framework to investigate superconducting materials. Such materials have the potential to revolutionise our energy supply. “When you transport electricity over large distances via standard copper cables, a lot of energy is lost. However, superconductors are capable of carrying electric energy without any friction loss,” points out Professor Thomale. “If we used superconducting cables to connect a city with another power plant, the energy loss would be zero. So we could actually produce electricity in a much more de-localised fashion than we can today.” The second potential technological application of the project’s research is in using these topological quantum states of matter to define quantum bits (qubits), which are the unit of information in the field of quantum computing. In contrast to the classical bit used in conventional computers, which can be one of only two values, qubits can be in a superposition that combines both. “Today’s computers are basically comprised of a series of manipulations of 0s and 1s. These qubits would replace the classical bits, and would
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allow us to define a totally new architecture of how computers can work. A huge community of scientists is currently working on various branches of this direction,” outlines Professor Thomale. This would represent an important step in the development of quantum computers, which could potentially solve complex problems much more quickly than conventional computers. However, while Professor Thomale is interested in exploring potential commercial applications of his work, he remains particularly committed to continuing his research into fundamental questions. “The diversity and richness of condensed matter physics in this era is simply incredible,” he enthuses. A lot of current research centres on bringing high-energy physics into tabletop condensed matter experiments. “That’s one of the big areas of reserach, in which I expect to see some of the biggest discoveries unfolding in the upcoming decades,” outlines Professor Thomale. This is an exciting time in solid state physics, with Professor Thomale saying there is enormous scope for further investigation, at a fraction of the cost incurred in other large-scale high-energy physics projects such as the LHC. Topological phases are vital to contributing to this direction. “Very often these topological quantum states of matter come along with new effective degrees of freedom, i.e. quasiparticles, that are unheard of,” he explains. This could also allow researchers to re-visit concepts as the Majorana fermion, which was put forward by the mysterious Italian physicist Ettore Majorana in 1937. “Majorana made amazing predictions, and a lot of people in high-energy physics were very excited by them, but they have not been unambiguously discovered in e.g. the double beta decay. Now researchers are very close to achieving this in solid state physics,” continues Professor Thomale.
Full Project Title Emergence of Topological Phases from Electronic Interactions (TOPOLECTRICS) Project Objectives In the TOPOLECTRICS ERC starting grant research plan, we investigate topological quantum phases which result from electronic interactions. The key objective is to provide a rigorous link between bare electronic models and low energy effective models hosting emergent topological quantum phases. Project Funding 1.3 million Euros Contact Details Principal Investigator, Professor Ronny Thomale Julius-Maximilians Universität Würzburg Institut für Theoretische Physik I (TP1) Am Hubland D-97074 Würzburg T: + 0931 31 86225 E: rthomale@physik.uni-wuerzburg.de W: https://erc.europa.eu/projects-andresults/erc-funded-projects/topolectrics
Professor Ronny Thomale
Ronny Thomale is a Professor of Theoretical Physics at the University of Wuerzburg. He gained his PhD from the University of Karlsruhe in 2008, after which he worked at several universities in both Europe and America, before taking up his current position in September 2013. His main area of research is the theoretical description of strongly correlated electron states.
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