Macroscopic superpositions and gravimetry with quantum magnetomechanics

• Published in: Scientific reports 2016-11, Vol.6 (1), p.37495-37495, Article 37495
• Main Authors: Johnsson, Mattias T., Brennen, Gavin K., Twamley, Jason
• Format: Article
• Language: English
• Subjects: 639/766/483/1139; 639/766/483/1255; Calibration; Gravimetry; Gravity; Humanities and Social Sciences; Interferometry; multidisciplinary; Noise; Science; Spatial discrimination
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep37495

Precision measurements of gravity can provide tests of fundamental physics and are of broad practical interest for metrology. We propose a scheme for absolute gravimetry using a quantum magnetomechanical system consisting of a magnetically trapped superconducting resonator whose motion is controlled and measured by a nearby RF-SQUID or flux qubit. By driving the mechanical massive resonator to be in a macroscopic superposition of two different heights our we predict that our interferometry protocol could, subject to systematic errors, achieve a gravimetric sensitivity of Δ g / g  ~ 2.2 × 10 −10  Hz −1/2 , with a spatial resolution of a few nanometres. This sensitivity and spatial resolution exceeds the precision of current state of the art atom-interferometric and corner-cube gravimeters by more than an order of magnitude, and unlike classical superconducting interferometers produces an absolute rather than relative measurement of gravity. In addition, our scheme takes measurements at ~10 kHz, a region where the ambient vibrational noise spectrum is heavily suppressed compared the ~10 Hz region relevant for current cold atom gravimeters.