Defence
Date: January, 23rd, 2026 at Department of Chemistry, "Kjemibygningen".
Trial lecture, title: Theoretical foundations of van der Waals interactions.
PhD thesis, title: A Mathematical Analysis of Coupled Cluster Theory and Density Functional Theory.
Main research findings
Quantum mechanics governs the behavior of atoms and molecules and underpins the properties of nearly everything we can observe. Its laws can be expressed through a single equation —the Schrödinger equation —which researchers use to simulate chemical reactions and predict chemical properties. Such simulations are essential tools in the development of new materials and pharmaceuticals.
This PhD thesis focuses on two cornerstone simulation methods in quantum chemistry: coupled-cluster theory and density functional theory, and establishes a rigorous mathematical foundation for them using advanced tools from functional analysis and C*-algebra.
The thesis consists of three scientific articles addressing key theoretical challenges. The first develops a framework for estimating errors in coupled-cluster calculations, increasing confidence in computational results. The second analyzes the time-dependent bivariational principle, a fundamental concept underlying time-dependent quantum simulations. The third proposes a new, reduced mathematical formulation of density functional theory, offering a more elegant approach to studying electron density. Together, these contributions strengthen the mathematical underpinnings of simulation methods that chemists rely on daily to discover new medicines and technologies.
Commitee, supervisors and chair of defence
Adjudication committee
Professor Eric Cances. Ecole des Ponts ParisTech, France.
Doctor Mohammad Hassan. Technische Universität München, Germany.
Professor Unni Olsbye. Department of Chemistry, University of Oslo, Norway.
Supervisors
Associate Professor Simen Kvaal. Department of Chemistry, University of Oslo, Norway.
Professor Nadia Slavila Larsen. Department of Mathematics, University of Oslo, Norway.
Professor Sergiy Neshveyev. Department of Mathematics, University of Oslo, Norway.
Chair of defence
Professor Ola Nilsen. Department of Chemistry, University of Oslo, Norway.
Funding
RCN CoE program, Hylleraas Centre. RCN Large Interdisciplinary Researcher Project (Fellesløft IV) QOMBINE: “Mathematics for quantum computation and many-body theory”, https://www.mn.uio.no/math/english/research/projects/qombine/.