It has become one of the major problems of theoretical physics to understand the interplay between our most successful theories, quantum mechanics and general relativity which necessitates experiments or observations at the interface of the two theories. In addition, the race in the development of space-based quantum technologies, where quantum resources are generated and probed locally or are exchanged over thousands of kilometers through the inhomogeneous gravitational field of Earth, fuels the need to understand the influence of general relativistic effects on quantum resources also from a practical point of view.

A particular example of an interesting fundamental effect at the interface of quantum mechanics and general relativity is the generation of entanglement between the internal energy structure of a quantum system and its external (motional) degrees of freedom (DOFs) due to gravitational time dilation or redshift. In this talk, I will present the results of our research on these entanglement dynamics due to gravity for photonic states and quantum memories in Mach-Zehnder and Hong-Ou-Mandel interferometry setups in the gravitational field of the earth [1]. Chances are good to witness the effect with near-future technology. This would represent an experimental test of theoretical modeling combining a multi-particle effect predicted by the quantum theory of light and an effect predicted by general relativity. Our article also gives the first analysis of relativistic gravitational effects on space-based quantum memories which are expected to be an important ingredient for global quantum communication networks.