The QUANTUS Project- Theory in the Ulm Group Investigating the properties of Bose-Einstein condensates under microgravity conditions and developing methods for atom interferometry.

Atom interferometry provides a unique opportunity not only for probing the foundations of physics at the interplay of relativity and quantum theory, but also for devising diverse, compact applications like sensors. In this spirit, the long-standing and fruitful QUANTUS collaboration investigates the dynamics of Bose-Einstein condensates under microgravity conditions and its application to atom interferometry. In particular, the QUANTUS theory group in Ulm focuses on a fundamental modelling of the light-matter dynamics, its impact on interferometric experiments, as well as potential setups to improve sensitivitity in the test of relativistic physics and fundamental principles. In this contribution, we will present an overview of the current work of the QUANTUS theory group in Ulm, and provide a perspective on upcoming projects of the newly starting QUANTUS+ collaboration.