Quantum sensing for gravity cartography
Ben Stray1, Andrew Lamb1, Aisha Kaushik1
1Midlands Ultracold Atom Research Centre, School of Physics and Astronomy, University of Birmingham, Birmingham, UK.
Nature
|February 24, 2022
Summary
A new quantum gravity gradient sensor overcomes limitations in geophysical surveying. This practical instrument rapidly maps underground features, enabling detailed subsurface exploration for various applications.
Area of Science:
- Geophysics and Quantum Sensing
Background:
- Gravity sensing is vital for geophysics, climate research, and geodesy.
- Current gravity cartography is limited by long measurement times for noise reduction, hindering metre-scale underground feature resolution.
Purpose of the Study:
- To develop a practical quantum gravity gradient sensor overcoming limitations of existing methods.
- To demonstrate the sensor's capability in high-resolution underground surveying.
Main Methods:
- Designed a quantum gravity gradient sensor that suppresses seismic, laser, thermal, magnetic, and tilt noise.
- Achieved a statistical uncertainty of 20 E (20 x 10^-9 s^-2).
- Conducted a 0.5-metre spatial resolution survey over an 8.5-metre line, detecting a 2-metre tunnel.
Main Results:
- Successfully detected a 2-metre tunnel with a signal-to-noise ratio of 8.
- Determined tunnel centre horizontally to ±0.19 metres and depth to (1.89 -0.59/+2.3) metres using Bayesian inference.
- Demonstrated that reduced vibrational noise directly translates to shorter mapping times.
Conclusions:
- The developed quantum gravity gradient sensor offers practical, high-resolution subsurface mapping.
- The sensor's capabilities are suitable for diverse applications including aquifer monitoring, archaeology, and infrastructure development.
- This technology provides a novel approach for underground exploration and risk assessment.
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