Dr. Rainer Kaltenbaek, University of Vienna
Abstract
Recent developments in space technology like micro-propulsion systems for drag-free control, thermal shielding, ultra-stable laser sources and stable optical cavities set an ideal stage for quantum optomechanical experiments with optically trapped dielectric spheres as well as for matter-wave interferometry in general. Here, we will provide an overview of the results of recent studies aiming at the realization of a space mission to test the foundations of quantum physics in a parameter regime orders of magnitude beyond existing experiments. In particular, we will discuss DECIDE (decoherence in a double-slit experiment), which is a scientific instrument part of the possible future space mission MAQRO (macroscopic quantum resonators). DECIDE aims at preparimg and then studying a Schrödinger-cat-type state, where a dielectric nanosphere of around 100nm radius will be in a superposition of being in two clearly distinct positions at the same time. This superposition leads to double-slit-type interference, and the visibility of the interference pattern will be compared to the predictions of quantum theory. This approach allows for testing for possible deviations from quantum theory as our test objects approach macroscopic dimensions. With DECIDE, it will be possible to distinctly test several prominent theoretical models that predict such deviations, for example: the Diósi-Pensrose model, the continuous-spontaneous-localization model of Ghirardi, Rimini, Weber and Pearle, and the model of Károlyházy. We will present recent progress in ground-based proof-of-principle experiments of central technologies for space-based matter-wave experiments like DECIDE with macroscopic objects, and we will discuss the possibility of hosting additional scientific instruments with similar technical requirements on MAQRO.