Testing quantum physics in space using optically trapped nanospheres

TL;DR

This paper discusses the potential of space-based quantum optomechanical experiments using optically trapped nanospheres to test the foundations of quantum physics and explore possible deviations at macroscopic scales.

Contribution

It presents an overview of recent studies and proposes the DECIDE experiment to create and analyze Schrödinger-cat states of nanospheres in space, testing quantum theory against alternative models.

Findings

Proposal for space-based quantum experiments with nanospheres

Potential to test deviations from quantum mechanics at macroscopic scales

Comparison of interference patterns to quantum theory predictions

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 platform for quantum optomechanical experiments with optically trapped dielectric spheres. Here, we will provide an overview of the results of recent studies aiming at the realization of the space mission MAQRO to test the foundations of quantum physics in a parameter regime orders of magnitude beyond existing experiments. In particular, we will discuss DECIDE, which is an experiment to prepare and then study a Schr\"odinger-cat-type state, where a dielectric nanosphere of around 100nm radius is prepared 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 Di\'osi-Pensrose model, the continuous-spontaneous-localization model of Ghirardi, Rimini, Weber and Pearle, and the model of K\'arolyh\'azy.