The adjudication committee consisted of Prof. Piotr Piecuch, Michigan State University, Dr. Thorsten Rohwedder, Institut für Mathematik, Humboldt-Universität zu Berlin, and Prof. Unni Olsbye, Department of Chemistry, University of Oslo. Fabian was supervised by Dr. Simen Kvaal and Dr. André Laestadius at the Hylleraas Centre in Oslo. The Chair of the Defense was Prof. Stian Svelle, Department of Chemistry, University of Oslo. Because of the ongoing corona pandemic, the disputation was carried out online.
We congratulate Fabian with his trial lecture and the successful defence of this thesis.
Here is Fabian’s own summary of his thesis:
The increase in computational power and the substantial advances in in silico method development of the past decades have promoted computational chemistry, in particular quantum chemistry, to a central branch of modern chemistry. Quantum-chemical simulations are today routinely performed by thousands of researchers in chemistry and related areas of research, complementing painstaking and costly laboratory work. Important examples are the design of new compounds for sustainable energy, green catalysis, and nanomaterials.
While the underlying mathematical theory is, on a fundamental level, well-described, its governing equation, namely, the many-body Schrödinger equation, remains numerically intractable. The fermionic many-body problem poses one of today's most notorious computational challenges. Over the past century, numerous numerical approximation techniques of various levels of cost and accuracy have been developed. One of the most successful approaches is coupled-cluster theory, a cost-efficient high-accuracy method, which is subject of this thesis.