After a long hiatus, I want to reactivate this blog. The latest (tough not so recent) piece of news is that I have defended my Habilitation thesis in January (2026). I can now officially supervise PhD students. Two of my PhD students had already defended their thesis before that, but I was never officially their advisor (technically not even their co-advisor). Now finally, I can manage everything without bothering a more senior colleague.

Usually, the Habilitation thesis is more of a compilation of summaries, that one assembles last minute to fulfill the technical requirements for the defense — the real evaluation being done from the candidate’s CV. But graphomania took me over, and I ended up writing something quite long about my recent adventure in quantum field theory. It’s an overview of the intense efforts to make relativistic continuous matrix product states work, with a discussion of recent developments (some of which were not fully finished when I wrote the manuscript). Because I couldn’t help it, I added some borderline philosophical discussion about why I thought it was a good idea in the first place. The topic is pretty niche, but I am hoping it might be interesting for the handful of people interested in this approach. The manuscript itself, with its admin part stripped off, is on arxiv for everyone to read.