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Logo: Sonderforschungsbereich geo-Q
Logo Leibniz Universität Hannover
Logo: Sonderforschungsbereich geo-Q
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geo-Q mission

The aim of geo-Q is to explore new frontiers and techniques for the determination of the Earth’s gravitational field its temporal variations by monitoring the global and regional mass redistribution. Understanding the processes relevant for these changes such as the melting of the polar ice sheets, the contribution of water influx to sea level rise, and changes in the hydrological cycle allows the scientific community to better quantify and conceive climate change.

geo-Q benefits from synergies with quantum metrology achieving major advancements in accuracy and focuses on three new measurement techniques that primarily address three goals:

  •  To track the motion of test masses in the gravitational field with nanometer accuracy and beyond, we study spaceborne laser interferometric distance and acceleration measurements. We are designing instruments for ranging between satellites using interferometers linking multiple test mass constellations within one satellite. 
  • We are developing atomic gravity sensors, based on the principles of atomic interferometry, that are capable of (quasi) continuous absolute gravity measurements on ground with μGal accuracy and better. We advanced the physics of sensors in the ultra-cold temperature regime and investigate their potential for monitoring geophysical processes involving regional mass variations in the water cycle and in the solid Earth with appropriate sampling in space and time. 
  • We established the quantum metrology of long-distance frequency comparisons to observe the gravitational frequency redshift with optical atomic clocks connected by phase-stabilized optical fiber links at the 10−17 precision level and lower. We are using the observations to apply – for the first time – the principles of relativistic geodesy to directly determine differences of the geopotential, the geoid and heights in points of geodetic networks.  

Find out more about our research areas.