## Scientific Talks

We calculate the correlation energy of the mean-field Fermi gas by bosonizing collective particle-hole pair excitations; this makes the random phase approximation rigorous as an upper bound.

- Conference "Dynamics, Equations and Applications" (DEA 2019), Kraków (September 2019)
- Conference "QMath 14: Mathematical Results in Quantum Physics", Aarhus University (August 2019)
- Conference "On Mathematical Aspects of Interacting Particle Systems in Low Dimension", FernUniversität Hagen (June 2019)
- Mathematical Physics Seminar, University of Vienna (June 2019)
- Workshop "Mean-Field and other Effective Models in Mathematical Physics", Fondation Les Treilles (May 2019)
- Workshop "Many-body theory, effective equations and PDEs", Mittag-Leffler Institute, The Royal Swedish Academy of Sciences, Stockholm (March 2019)
- Seminar at Gran Sasso Science Institute, L'Aquila (7 March 2019)
- Seminar at Università degli Studi Roma Tre (27 November 2018)
- Quantum Lunch, University of Copenhagen, one hour seminar talk (7 November 2018)
- ICMP 2018 Montreal, contributed talk (July 2018)

Reformulation of the Dirac-Frenkel principle in terms of reduced density matrices and application to the derivation of Hartree-Fock and Bogoliubov-de-Gennes equations:

- Spectral Days, Stuttgart, contributed talk (April 2017)

Interaction corrections to spin-wave theory of the ferromagnetic quantum Heisenberg model, and perturbative analysis of spin-waves at low temperature:

- IST Austria, Klosterneuburg (February 2018)
- LMU München (December 2017)
- IST Austria, Klosterneuburg (October 2016)

Derivation of the time-dependent Hartree-Fock equation for pure and mixed fermionic states in the mean-regime, and derivation of the Vlasov equation:

- Seminar Analysis, Math-Phys, and Quantum at SISSA Trieste (December 2016)
- Mathematical Challenges in Quantum Mechanics, Bressanone, contributed talk (February 2016)
- Università degli Studi Roma Tre (September 2015)
- Università degli Studi dell'Insubria, Como (April 2015)
- Quantum Lunch, University of Copenhagen (February 2015)
- Seminar, Università Roma Tre (October 2014)
- Seminar, University of Mannheim (February 2014)
- Warwick Statistical Mechanics Seminar, University of Warwick (December 2013)
- Mathematical Physics Seminar, University of Bristol (December 2013)
- Oberseminar Analysis, University of Stuttgart (November 2013)

Quantitative Derivation of the Gross-Pitaevskii equation:

- The Time-Dependent Gross-Pitaevskii Equation and its Derivation, Fields Institute Toronto (August 2016, invited talk)
- Quantum Lunch Minitalk, Copenhagen (November 2015)
- QMath 12, Berlin (September 2013, contributed talk)

Slides of my PhD defence:

- PhD Defence, University of Bonn (April 2014)

Anderson localization at large disorder on a lattice (method of fractional moments):

- Working group seminar Bonn (June 2012)

Fermionic coherent states with and without Grassmann numbers:

- Working group seminar Bonn (October 2012)

Dynamics of the radiative decay of excited atoms, rate of relaxation:

- Short talk Berlin WIAS (February 2011)
- Blackboard talk Bonn HCM (February 2011)
- Mathematical Physics Seminar Heidelberg + handwritten notes (October 2010)

Existence of asymptotic fields in non-relativistic quantum electrodynamics:

- Working group seminar Stuttgart (July 2010)

## Undergraduate Studies: Seminar Talks

In a 2+1 dimensional nonlinear Sigma model with Hopf term there exist
topological excitations (skyrmions), which can have arbitrary spin (not
necessarily integer or half-integer) and arbitrary quantum statistics
(arbitrary phases under permutation
of particles). Skyrmions have be found in experiments, see e.g. X. Z. Yu et al.

A short theoretical introduction to this interesting topic can be found
in the book "Quantum Field Theory" by Kerson Huang (Wiley 1998) in the
chapter on topological excitations.

- Seminar talk (July 2009)
- Additional materials (July 2009)

Physics talks (in German) at the "Naturwissenschaftliches Kolleg" of the Studienstiftung (German National Academic Foundation).

- Quantitative Derivation of the Gross-Pitaevskii Equation (November 2012)
- Exact Renormalisation Group and Asymptotic Safety of Gravity (November 2011)
- Homotopie-Gruppen für Physiker, Anyonen in 2+1 Dimensionen (Oktober 2010)
- Konforme Feldtheorie (April 2010)
- Majorana-Spinoren (September 2008)
- Farbladungsspiel (September 2008)
- Das Wu-Experiment (April 2008)