Gravitational Interferometry with Entangled States in Optical Fibres


All four known interactions occurring in nature can be described either by Einstein's general relativity or by quantum field theory. Over the last decades physicists tried to put these two pillars of modern physics on a common foundation. In doing so, they have been limited by lack of experiments at the interface of these two frameworks. Both theories have been independently verified with astonishing precision, but all verifications to date have come without drawing on concepts from the other theory.  

The goal of GRAVITES is to perform experiments at the interface of quantum physics and general relativity. For the first time, we will measure gravitational properties of single and entangled photons in the background of Einstein’s gravity. To this end, GRAVITES aims to combine four complementary disciplines: quantum photonics and precision interferometry guided by expertise in general relativity and quantum field theory. The synergy among the research groups will realize a large-scale fiber interferometer with an unprecedented level of precision.  

Since the sensitivity of GRAVITES’s apparatus will exceed all present large-scale fiber-based quantum interferometers by several orders of magnitude, the two experimental teams must combine cutting-edge technologies in their respective fields for advancing single-photon interferometry. These developments are also of direct relevance for many other applications such as quantum metrology and quantum sensing. In parallel, the theory teams will investigate the combined effects of gravitation and field quantization in dielectric waveguides.  

With this united effort GRAVITES is in the unique position to explore new physics that determines the gravitational properties of quantum superposition and quantum entanglement. This will allow us to take a big step towards addressing how gravity interacts with the quantum world.