PhD Position: Structural Generalization in Transformer-based LLMs
*Start date:* as soon as possible *Application deadline:* 11 May 2026
The research groups of Michael Hahn https://www.mhahn.info/ and Alexander Koller https://www.coli.uni-saarland.de/~koller/ are jointly looking for a PhD student. The student will be jointly advised by both professors.
The position is funded through the new project “Structural generalization in transformer-based LLMs”, which is part of the DFG Special Priority Program Robust Assessment and Safe Applicability of Language Modeling: Foundations for a New Field of Language Science and Technology https://www.lasting-spp.org/. The goal of the SPP is to bring together research in linguistics and LLMs so they can mutually inform each other.
The starting point of the project is the observation that transformers struggle with /structural generalization:/ they do not perform well on test instances that are more complex than the training instances. We see this e.g. when parsing complex sentences or when managing complex reasoning chains. In the project, we want to develop theory that explains this limitation, carry out empirical research to pinpoint the transformer’s capabilities, understand them through mechanistic interpretability, and find ways to improve structural generalization in transformers. Methods range from formal language theory to training and prompting-based experiments to circuit analysis. We will carry out the project in collaboration with Will Merrill https://lambdaviking.com/ and Yuekun Yao https://ykyaol7.github.io/.
This is a position on the German TV-L E13 scale https://oeffentlicher-dienst.info/c/t/rechner/tv-l/west?id=tv-l-2023 (100%). The starting salary of a 100% TV-L E13 position is a bit over 50,000 Euros per year and increases with experience. The position is funded for three years; we expect to be able to extend it to four. We can be flexible with the start date (within the year 2026).
*Requirements*
We are looking for candidates who have finished, or are about to complete, an excellent Master’s degree in computer science, computational linguistics, or a related discipline. The ideal candidate will have outstanding programming skills and algorithmic understanding; a strong understanding of current methods in machine learning; and strong communication skills in English (spoken and written).
*About the group*
Saarland University is one of the leading centers for computational linguistics in Europe, and offers a dynamic and stimulating research environment. The Department of Language Science and Technology https://www.lst.uni-saarland.de/en/ consists of about 100 research staff in ten research groups in the fields of computational linguistics, psycholinguistics, and language science. It hosts the SFB 1102 “Information Density and Linguistic Encoding” https://sfb1102.uni-saarland.de/.
Michael Hahn and Alexander Koller are members of the Research Training Group “Neuroexplicit Models of Language, Vision, and Action” https://www.neuroexplicit.org/, one of the largest centers for research on neurosymbolic models in the world. They actively collaborate with colleagues at the university’s computer science department, the Max Planck Institute for Informatics https://www.mpi-inf.mpg.de/home, the Max Planck Institute for Software Systems https://www.mpi-sws.org, and the CISPA Helmholtz Center for Information Security https://cispa.de/en. The Saarland Informatics Campus https://saarland-informatics-campus.de/en brings together 1000 researchers and 2600 students from 81 countries; SIC faculty have won roughly 50 ERC grants.
Saarland University is located in Saarbrücken https://en.wikipedia.org/wiki/Saarbr%C3%BCcken, a city of roughly 180k people in the tri-border area of Germany, France, and Luxembourg https://quattropole.org/en. Saarbrücken combines a lively culture scene with a relaxed atmosphere, and is quite an affordable place to live in. Our department maintains an international and diverse work environment. The primary working language is English; learning German while you are here will make it easier to connect with the local culture, but is not necessary for your work.
*How to apply*
Please submit your application by email to apply-ak@coli.uni-saarland.de and include the reference number W2846 https://www.uni-saarland.de/fileadmin/upload/verwaltung/stellen/Wissenschaftler/W2846.pdf. Preference will be given to applications received by 11 May 2026.
Include a single PDF file with the following information:
1. a statement of research interests that motivates why you are applying for this position and outlines your research agenda; 2. a full CV including your list of publications; 3. scans of transcripts and academic degree certificates; 4. the names, affiliations, and e-mail addresses of two people who can provide letters of reference for you.
Saarland University especially welcomes applications from women and people with disabilities.
The legally binding version of this job ad is here: W2846 https://www.uni-saarland.de/fileadmin/upload/verwaltung/stellen/Wissenschaftler/W2846.pdf.