GRK 1995:  Quantum Many-Body Methods in Condensed Matter Systems

• Subject Area: Condensed Matter Physics
• Term: from 2014 to 2023
• Website: Homepage
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 240766775

Many-body effects of quantum-mechanical nature not only lead to important emergent collective phenomena in extended condensed matter systems, such as superconductivity and magnetism, but also play a crucial role in various meso- and nanoscopic systems. Quantum many-body physics, thus, constitutes a fascinating field of basic research with implications for applications. Theoretical physics faces three challenges: (a) to gain a deeper understanding of correlation effects and to obtain (b) a more realistic as well as (c) a more precise description of the emergent phenomena. We addressed these central issues in the first funding period of our RTG, and we intend to pursue them further in the proposed second period, with the ultimate goal of having an impact on the development of functional materials and nano-electronics. Since the progress, which can be achieved through a single, highly specialized modern quantum many-body method, is limited, our research strategy is to systematically combine complementary techniques and to exploit their synergy. An example is the combined application of ab-initio and strongly correlated methods to investigate modern materials. A further one is the application of methods developed recently in quantum information science to many-body models. In the past, method combination has proved its power for certain, selected problems. During the first funding period of the RTG, it was pursued on a much broader basis of techniques. In this context, the RTG qualification program for doctoral researchers is an indispensable means of attaining our goals. Modern quantum many-body methods, both analytical as well as numerical, are technically challenging. Early career researchers usually learn and apply only one method in their Master’s and PhD studies. Taking advantage of our qualification and supervision program, our RTG graduates have gained first-hand experience in the development and application of, at least, two such techniques. The Aachen-Jülich area, with its many researchers and its long and successful history in the field of quantum many-body methods, constitutes an ideal environment sustaining a RTG with this challenging aim. We have broad research experience, international collaborations and standing, as well as the teaching capacity to offer an extensive and demanding RTG program, as we have demonstrated in the first funding period. The expertise of the contributing researchers covers application-oriented ab-inito methods, numerical many-body approaches, non-equilibrium techniques, renormalization group methods, as well as quantum information based approaches.

• DFG Programme: Research Training Groups
• Applicant Institution: Rheinisch-Westfälische Technische Hochschule Aachen
• Participating Institution: Forschungszentrum Jülich
• Spokesperson: Professor Dr. Volker Meden
• Participating Researchers: Professor Dr. Stefan Blügel; Dr. Theo A. Costi; Professor Dr. Carsten Honerkamp; Dr. Severin Jakobs; Professor Dr. Dante Marvin Kennes; Professor Dr. Erik Koch; Professorin Dr. Eva Pavarini; Dr. Mikhail Pletyukhov; Professor Dr. Herbert Schoeller; Professor Dr. Maarten Rolf Wegewijs; Professor Stefan Wessel, Ph.D.