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Logo: Institut für Quantenoptik/Leibniz Universität Hannover
Logo Leibniz Universität Hannover
Logo: Institut für Quantenoptik/Leibniz Universität Hannover
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Quantum Gravimeter QG-1

Overview of the project

Fig.1: CAD drawing of the sensor head

The major goal of the project is the demonstration of a compact and robust transportable quantum gravimeter operated with ultra-cold atomic ensembles generated by an atom chip. The two main tasks are:

  • exploitation of Bose Einstein condensates (BECs) for gravimetry, characterization for field application and comparison to state-of-the-art classical gravimeters, and
  • pushing the limits of the sensitivity and accuracy of quantum gravimeters to the sub-μGal level by employing ultra-cold atomic ensembles and exploring novel concepts for advancing quantum sensors in general.

This prototype (Fig.1) will be formed by bringing together several methods that have been rapidly evolving during the last years, especially within the projects of the QUANTUS cooperation. Most importantly, the development of atom chips to high-flux sources of ultra-cold neutral atoms allows for the application of these for atom interferometry. This paves the way for sub-μGal uncertainty in atom interferometry. Based on these expertises on the construction and optimization of such atomic sources and high precision atom interferometry, we will be able to overcome today’s limitations in absolute accuracy of atomic gravimeters. This will represent the next generation in atom-interferometer-based absolute gravimetry.

Fig.2: Gravitational field map of Scandinavia

The transportable quantum gravimeter is tailored to the needs of field applications in geodesy which are pursued by the group of Prof. Müller at the IfE. The performance will be studied in detail in comparison to the IfE gravimeters, both in short-period gravity recordings compared to a gPhone gravimeter and in absolute gravity measurements in parallel with the FG5X-220. The field applicability of the QG-1 will be demonstrated in measurements at stations of the IfE (Hannover, Ruthe), and also in Clausthal-Zellerfeld at the Clausthal University of Technology. Such measurements will be extended to episodic measurements for tracking long-term gravity variations in the Fennoscandian land uplift region (Fig.2), and wind-driven sea loading effects of the Baltic sea, as well as gravity effects of local hydrology in long-term gravity recording.