Stephan Weis

Mathematician





profile
I enjoy working on mathematical problems, mostly in geometry, matrix analysis, and functional analysis. Many of my past projects were inspired by problems of quantum information theory.
I got my PhD in mathematics in 2009 from the University of Erlangen-Nuremberg, Germany, where I wrote my thesis under the supervision of Andreas Knauf and Nihat Ay in the mathematical physics group. My thesis deals with the geometry of non-commutative exponential families (Gibbs states) with several parameters. I completed five post-doctoral research programs:
2010/2011, I worked on convex geometry at University Erlangen-Nuremberg.
2011/2014, I studied the continuity of inference maps with a grant from Arleta Szkoła, in her project on quantum statistics at Max Planck Institute for Mathematics in the Sciences in Leipzig, Germany.
2015/2016 at University of Campinas, São Paulo, Brazil, I began to study the algebraic geometry of joint numerical ranges (linear images of the convex set of density matrices), which led to a paper in the journal SIAGA in 2021.
2016/2018, Jérémie Roland, Atul S. Arora, and I developed quantum algorithms for weak coin flipping at Ecole Polytechnique de Bruxellles, Belgium (results published in a STOC paper in 2019).
2018-07/12, I resumed work on the algebraic geometry of joint numerical ranges at University of Coimbra, Portugal.
Thereafter, I completed a research project on the Choquet theory of energy-constrained density operators, which is motivated by problems of quantum communication. I also completed a project on reduced density matrices.
2020/2023, I taught in secondary schools (Gymnasium) in Berlin, Germany.
In addition to mathematics, I am very much concerned about human-caused environmental damage, and climate change, in particular. As an individual, whenever possible, I strive to minimize my carbon footprint. I've collected a few links (in German) in the section "Weblinks zum Thema Klimawandel" below.


research in mathematics
publications: articles, theses
presentations: slides, videos, posters
web profiles
trivia: Erdős number = 3, Einstein number = 4


Weblinks zum Thema Klimawandel (in German)
BLOG: KlimaLounge von Stefan Rahmstorf, Professor für Physik der Ozeane
Volker Quaschning, Professor für Regenerative Energiesysteme
ins Deutsche übersetzte Blog-Artikel von Skeptical Science
Cranky Uncle, Spiel zur Stärkung der Abwehrkräfte gegen Falschinformationen (auch auf Deutsch und im Browser spielbar)
website last modified on 27 February 2024
free webhosting powered by