2020/09/21 by Tobias Westphal, Hans Hepach, Westphal, Tobias +5 · 2 citations
Physics and Astronomy · #Classical Physics (physics.class-ph) #Cold Atom Physics and Bose-Einstein Condensates #Experimental and Theoretical Physics Studies #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Instrumentation and Detectors (physics.ins-det) #Mechanical and Optical Resonators #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2009.09546
openalex publication_date 2020/09/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We demonstrate gravitational coupling between two gold spheres of approximately 1mm radius and 90mg mass. By periodically modulating the source mass position at a frequency f=12.7mHz we generate a time-dependent gravitational acceleration at the location of the test mass, which is measured off resonance in a miniature torsional balance configuration. Over an integration time of 350 hours the test mass oscillator enables measurements with a systematic accuracy of 4E-11m/s2 and a statistical precision of 4E-12m/s2. This is sufficient to resolve the gravitational signal at a minimal surface distance of 400mum between the two masses. We observe both linear and quadratic coupling, consistent in signal strength with a time-varying 1/r gravitational potential. Contributions of non-gravitational forces could be kept to less than 10% of the observed signal. We expect further improvements to enable the isolation of gravity as a coupling force for objects well below the Planck mass. This opens the way for precision tests of gravity in a new regime of isolated microscopic source masses.