Finn Lasse Buessen

Hi, I am a theoretical physicist working on condensed matter systems. Currently, I am a Ph.D. student in the group of Prof. Dr. Simon Trebst at the Institute for Theoretical Physics, University of Cologne. You can find me at

Institute for Theoretical Physics

Zuelpicher Strasse 77

50937 Cologne


Office: 110

Phone: (+49) 221 470 4208

Email: fbuessen (at)

Research Interests

I am interested in the theory of strongly correlated systems, quantum magnetism, and the formation of quantum spin liquids. I have a strong background in software development, which I leverage in my research to push the limits of what we can achieve in modern computational physics.

At the moment I am working on state-of-the-art (pseudo-fermionic) functional renormalization group implementations that have proven to be powerful tools in the exploration of frustrated quantum magnetism, especially in three spatial dimensions.

Brief CV

since 06/2016
Ph.D. student in the group of Simon Trebst
M.Sc. at University of Cologne


A. Revelli, C.C. Loo, D. Kiese, P. Becker, T. Fr√∂hlich, T. Lorenz, M. Moretti Sala, G. Monaco, F.L. Buessen, J. Attig, M. Hermanns, S.V. Streltsov, D.I. Khomskii, J. van den Brink, M. Braden, P.H.M. van Loosdrecht, S. Trebst, A. Paramekanti, and M. Gr√ľninger

Spin-orbit entangled j=1/2 moments in Ba2CeIrO6 - a frustrated fcc quantum magnet


Finn Lasse Buessen, Max Hering, Johannes Reuther, and Simon Trebst

Quantum spin liquids in frustrated spin-1 diamond antiferromagnets

Phys. Rev. Lett. 120, 057201 (2018)

Finn Lasse Buessen, Dietrich Roscher, Sebastian Diehl, and Simon Trebst

Functional renormalization group approach to SU(N) Heisenberg models: Real-space RG at arbitrary N

Phys. Rev. B 97, 064415 (2018)

Dietrich Roscher, Finn Lasse Buessen, Michael M. Scherer, Simon Trebst, and Sebastian Diehl

Functional renormalization group approach to SU(N) Heisenberg models: Momentum-space RG for the large-N limit

Phys. Rev. B 97, 064416 (2018)

Finn Lasse Buessen and Simon Trebst

Competing magnetic orders and spin liquids in two- and three-dimensional kagome systems: Pseudo-fermion functional renormalization group perspective

Phys. Rev. B 94, 235138 (2016)

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