Cutting-edge Quantum Sensor Targets Climate Change

An ambitious new project, launched by the European Commission and supported by the Quantum Flagship, is set to transform Earth monitoring by providing more accurate data on changes in ice melt, groundwater depletion, and ocean circulation.

Called CARIOQA-PMP, the new €17 million project seeks to improve traditional gravity-sensing methods by incorporating the extraordinary capabilities of quantum sensors.

Materials on the Earth, like rocks, minerals and water, have different densities from place to place. The Earth’s gravity field is affected by the mass of these materials. The more mass in an area, the stronger the gravitational pull in a particular spot. When large masses move or change, such as ice melting and flowing into the ocean, or when groundwater is depleted, it changes the local gravity.

Traditional gravity mapping can detect these differences, which can tell us important things, like where underground water might be, how much ice is melting in the polar regions, or even help in finding natural resources.

But, looking at the Earth from outer space, the picture of gravity is somewhat unclear. While very advanced, traditional gravimeters struggle with weak gravitational signals from Earth when trying to measure fine-scale variations across different regions.

However, this new and improved quantum accelerometer will be the first of its kind to enhance its capabilities using quantum physics. This tool will enable scientists to see a complete gravity map of the Earth in a much ‘higher resolution’.

Christine Fallet, project coordinator of CARIOQA-PMP, said: “Traditional gravimeters, or classical electrostatic accelerometers, have some limitations in sensitivity and precision. However, they provide information that allows us to detect major ocean currents from Earth; smaller or more subtle features might not captured with enough detail or be missed completely. This is not satisfactory for accurate earth monitoring and studying the smallest changes in gravity caused by subtle shifts like small amounts of ice melting or minor groundwater depletion.

“The goal of the CARIOQA project is to develop groundbreaking quantum space-borne accelerometer technologies that can transform satellite-based Earth science. These advancements are set to play a pivotal role in monitoring climate change and supporting global efforts in developing mitigation and adaptation strategies.”

The new CARIOQA quantum technology is still in development, with the team employing a technique called Cold Atom Interferometry (CAI). CAI relies on the principles of quantum mechanics to examine and exploit the wave-like behaviour of atoms at extremely low temperatures.

When atoms are cooled to near absolute zero, they move almost in slow motion, allowing for extremely precise measurements with lasers. “When cooled,” Fallet said, “the atoms’ wave-like nature can be exploited to create interference patterns (similar to ripples in water overlapping). By analysing these patterns, we can measure the atoms’ acceleration with great precision.

Cold Atom Interferometry avoids some problems of older systems, producing clearer, more reliable data over time. When it comes to measuring gravity, CAI is like upgrading from a blurry old TV to a crystal-clear HD screen. This technology will give us a much sharper view of what’s happening to our planet.