Asbjørn Bækgaard Lauritsen

Contact

CNRS & CEREMADE, Université Paris-Dauphine, PSL University
Place du Maréchal de Lattre de Tassigny
75016 Paris, France
Office: B601
email: lauritsen@ceremade.dauphine.fr

About Me

Since November 2024, I am a postdoctoral researcher at Université Paris-Dauphine in the group of Mathieu Lewin. Prior to this, I did my Ph.D. at IST Austria with Robert Seiringer and my M.Sc. and B.Sc. in mathematics at the University of Copenhagen with Jan Philip Solovej.

My research interests are within the mathematics of many-body quantum systems and effective theories thereof.

Brief CV

Since 2024: Postdoctoral researcher, Université Paris-Dauphine
2020 – 2024: Ph.D., IST Austria
2018 – 2020: M.Sc. in mathematics, University of Copenhagen
2015 – 2018: B.Sc. in mathematics, University of Copenhagen

Detailed CV

Publications

Density Functional Theory

• Geometric Time-Dependent Density Functional Theory
  É. Cancès, T. Duez, J. van Gog, A. B. Lauritsen, M. Lewin, and J. Toulouse, Phys. Rev. Lett. 136, 256401 (2026)
  Highlighted in Physics Magazine and CNRS Le Journal (In French)
• Geometric theory of constrained Schrödinger dynamics with application to time-dependent density-functional theory on a finite lattice
  É. Cancès, T. Duez, J. van Gog, A. B. Lauritsen, M. Lewin, and J. Toulouse, Phys. Rev. A 113, 062222 (2026)

Dilute Fermi gases

• Momentum Distribution of the Dilute Fermi Gas
  N. Benedikter, E. L. Giacomelli, A. B. Lauritsen, and S. Lill, arXiv:2602.12067 (2026)
• Pressure of a dilute spin-polarized Fermi gas: Upper bound
  A. B. Lauritsen and R. Seiringer, arXiv:2407.05990 (2024)
• Ground state energy of the dilute spin-polarized Fermi gas: Lower bound
  A. B. Lauritsen and R. Seiringer, arXiv:2402.17558 (2024)
• Pressure of a dilute spin-polarized Fermi gas: Lower bound
  A. B. Lauritsen and R. Seiringer, Forum of Mathematics, Sigma 12, e78 (2024)
• Almost optimal upper bound for the ground state energy of a dilute Fermi gas via cluster expansion
  A. B. Lauritsen, Ann. Henri Poincaré 26, pp. 203–243 (2025)
• Ground state energy of the dilute spin-polarized Fermi gas: Upper bound via cluster expansion
  A. B. Lauritsen and R. Seiringer, J Funct Anal. 286 (7) p. 110320 (2024)
• (Supplementary material: Code on GitHub for calculating values of GGR-diagrams)

BCS theory

• Multi-band Superconductors have Enhanced Critical Temperatures
  J. Henheik, E. Langmann, and A. B. Lauritsen, Ann. Henri Poincaré (online first) (2026)
• Universal behavior of the BCS energy gap
  J. Henheik and A. B. Lauritsen, J. Spectr. Theory 15.1, pp. 305–352 (2025)
• Universality in low-dimensional BCS theory
  J. Henheik, A. B. Lauritsen, and B. Roos, Rev. Math. Phys. 36, 9, p. 2360005 (2024)
• The BCS Energy Gap at High Density
  J. Henheik and A. B. Lauritsen, J. Stat. Phys. 189, 5 (2022)
• The BCS energy gap at low density
  A. B. Lauritsen, Lett. Math. Phys. 111.20 (2021)

Miscellaneous

• Stochastic cellular automaton model of culture formation
  F. R. Klausen and A. B. Lauritsen, Phys. Rev. E 108.5 (2023)
  (Supplementary material: Code on GitHub and Research data)
• Floating Wigner crystal and periodic jellium configurations
  A. B. Lauritsen, J. Math. Phys. 62, 083305 (2021)

Proceedings/Reports

• Thomas–Fermi theory and the limit of a large atom
  A. B. Lauritsen, in Arbeitsgemeinschaft: Analysis of Many-Body Quantum Systems, Oberwolfach Rep. 22, no. 4, pp. 2529-2533 (2025)

Teaching

• Quantum Mechanics at Université Paris-Dauphine, Autumn 2025. Course material

Talks

Slides of previous talks can be found here

Theses

• Energies of Dilute Fermi Gases and Universalities in BCS Theory
  Ph.D. thesis, Institute of Science and Technology Austria (2024)
  
• A mathematical formulation of the Bardeen-Cooper-Schrieffer theory of superconductivity
  M.Sc. thesis in mathematics, University of Copenhagen (2020)
  (Supplementary material: Proof of Equation (5.8))
• Representations of the Poincaré Group
  B.Sc. thesis in mathematics, University of Copenhagen (2018)

Collaborators

Niels Benedikter, Éric Cancès, Théo Duez, Emanuela L. Giacomelli, Jari van Gog, Joscha Henheik, Frederik Ravn Klausen, Edwin Langmann, Mathieu Lewin, Sascha Lill, Barbara Roos, Robert Seiringer, Julien Toulouse,