Measuring the Gravitational Attraction of Milligram Masses

Combining general relativity and quantum mechanics into one unified theory remains a major unsolved problem in physics, in particular due to the lack of experimental data.

Probing systems on Planck scales, in which both gravity and quantum theory predict comparable effects, seems unfeasible in the near future.

This motivates the idea of investigating the quantum-gravity interface by measuring the gravitational interaction between two small masses with the eventual goal of placing these masses in quantum states.

Laboratory-scale experiments in the last four years include kg-sized masses influencing levitating particles, or torsion pendulum experiments, which have shown the gravitational interaction between 90 mg gold spheres.

However, such experiments are not designed to reach the quantum regime because either one of the objects is extremely large and thus clearly non-quantum, or the system is not designed to prepare objects in their motional ground state. Here, I propose mGramm: Measuring the Gravitational Attraction of Milligram Masses.

Within this project, I will develop and execute an experiment to measure the gravity originating from masses down to 10 mg, the smallest to record.

At the same time, mGramm will move gravity experiments into the world of cavity optomechanics, which promises a direct path to systems in which both source and test mass are in non-classical states.

The project builds upon this scientifically highly relevant topic with a multi-level dissemination plan to bring this fundamental research to as broad an audience as possible, while also acting as a training program for myself to improve my skills as a productive scientist in academia.