News - South China Morning Post
· collected 2026-09-05 · by Zhang Tong
A Chinese-German team of researchers has developed a new "floating compass" called LeMaMa that can detect extremely faint magnetic signals. The device operates at room temperature and is capable of measuring magnetic fields down to the femtotesla level, which is one quadrillionth of a tesla. This sensitivity could be useful for detecting dark matter particles or monitoring brain signals. The researchers' work was published in the journal Science on August 6.
Written by the local model on 2026-09-06,
using this article's own text rather than the other coverage of the
same event (that is the story summary below).
Story summary
A team of researchers from Peking University in China and Johannes Gutenberg University Mainz in Germany have developed an ultra-sensitive "floating compass" called LeMaMa. This device, which operates at room temperature, can detect magnetic signals that are a billion times fainter than the Earth's own magnetic field. The Levitated Magnet Magnetometer (LeMaMa) works by tracking a tiny needle that floats in mid-air with minimal friction, allowing it to measure magnetic fields down to the femtotesla level, an incredibly small unit of measurement. This advancement could have significant implications for the search for dark matter particles and monitoring brain signals. The device's combination of room-temperature operation, tiny components, and high sensitivity make it promising for fundamental physics experiments, according to Ji Wei, an assistant professor at Peking University and corresponding author of the study.
Written for “Dark Matter Detector” on 2026-09-07,
grounded in this article and the 0 other(s) covering the same event.
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No political leaning scored for article 5091 · logged 2026-09-06
Chinese researchers have developed a table-top
magnetic sensor that operates at room temperature and can spot magnetic signals a billion times fainter than the Earth’s own field.
asserted
that → develop → field
The Levitated Magnet Magnetometer (LeMaMa) functions like a compass with a needle that floats in mid-air with virtually no friction.
asserted
that → function → friction
By tracking the needle’s tiny deflections, the team can measure magnetic fields down to the femtotesla level – an advance that could widen the hunt for elusive
dark matter particles or monitor brain signals.
uncertain
that → track → signals
“The combination of room-temperature operation, tiny components and high sensitivity makes LeMaMa promising for fundamental physics experiments,” Ji Wei, assistant professor at Peking University’s school of physics and corresponding author of the study, told Guangming Daily on August 17.
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Wei → make → August
Magnetic fields are everywhere, ranging in strength from about 1.5 tesla for a hospital magnetic resonance imaging machine to the vanishingly weak femtotesla, or a quadrillionth of a tesla, generated by human brain activity.
asserted
fields → range → activity
Measuring the tiniest magnetic fields has long been a challenge.
asserted
Measuring → measure → fields
Now, scientists from China’s
Peking University and Johannes Gutenberg University Mainz in Germany have built the world’s first room-temperature ultraprecise
magnetometer based on a levitated magnet.
asserted
University → build → magnet
Their work was published in the journal Science on August 6.
asserted
work → publish → August
Until now, femtotesla-level measurements have mainly relied on two approaches.
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measurements → rely → approaches
One is the superconducting quantum interference device (Squid) magnetometer, which offers excellent sensitivity but must operate at cryogenic temperatures near absolute zero, requiring bulky and expensive liquid-helium cooling.
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which → offer → cooling
