A team of physicists from the Australian National University (ANU) has unveiled a novel device that could transform the future of high-precision rotation measurements and open new frontiers in the search for exotic physics, including dark matter.
Combining an atomic magnetometer with a gyroscope inside a tiny glass cell, the researchers have developed a technique that isolates magnetic noise – long considered a barrier in precision measurements – using laser pulses and a carefully mixed gas cocktail.
The breakthrough, detailed in the New Journal of Physics, is being hailed as a “fresh way” to decouple magnetic interference from rotation measurements, potentially leading to game-changing applications in quantum sensing, geophysics, and fundamental physics.
A Ghost in the Machine
At the heart of the innovation is a dual-gas mixture inside a compact, low-power glass cell: rubidium-87, an alkali metal sensitive to laser light, and xenon-129, a noble gas invisible to lasers – described by the team as acting “like a ghost.”
“Although the spins of both gases rotate around each other, the laser system only sees the alkali spin,” explained Professor Ben Buchler from ANU’s Department of Quantum Sciences and Technology (QST). “The noble gas is invisible but reacts to the magnetic field of the alkali – it’s like a ghost, whose presence is only revealed by the way the spin of the alkali dances around it.”
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By observing the alkali spin’s motion, the team can infer both the rotation and the magnetic field independently, overcoming the “pervasive” problem of magnetic noise.
How It Works: Lasers, Spins and Pulses
The device measures quantum spin, the same principle used in Magnetic Resonance Imaging (MRI), making it extremely sensitive to both magnetic fields and rotations.
Key to this decoupling is a synchronised pulse system:
- Laser pulses stimulate the rubidium’s electron spins.
- Magnetic field pulses drive the xenon’s nuclear spins.
By alternating the polarity of magnetic pulses and monitoring the precession (wobble) of the rubidium spin between pulses, the researchers could successfully isolate four separate values: rotation and magnetic field in both x and y directions.
“This co-magnetometer is a fresh way of looking at the magnetic noise problem and has the potential to overcome limitations that have haunted us for decades,” said Dr Morgan Hedges, lead author of the study.
Small Device, Big Potential
The prototype – notable for not requiring cryogenics and operating with low power – is already showing sensitivity levels competitive with the best current magnetometers and gyroscopes. Importantly, it’s not just about making better devices—it’s about exploring uncharted physics.
One major target? Dark matter.
“In some models of dark matter, axions could cause spin precession, and our technique would allow us to examine that,” said Professor Buchler. “It’s a table-top experiment that could help uncover new physics without the need for a billion-dollar particle collider.”
Part of a Global Effort
The QST group is contributing to the Global Network of Optical Magnetometers for Exotic Physics Searches (GNOME), a worldwide collaboration searching for subtle clues to new physical phenomena like axions.
The ability to measure rotational and magnetic fields simultaneously – and disentangle them – means the ANU device could become a cornerstone tool in dark matter research, navigation systems immune to magnetic interference, and beyond.
“We’re dancing with atomic ghosts to see the unseen,” said Dr Hedges. “No one has thought of a measurement system quite like this before, so every application we think of is new.”
Applications on the Horizon:
- High-precision inertial navigation (especially where GPS is unavailable)
- Geological surveys and planetary science
- Spacecraft navigation systems
- Laboratory-based dark matter detection
- Quantum sensing and fundamental physics experiments
As the lines between quantum technology and applied physics continue to blur, the ANU team’s innovation underscores the vast potential of small-scale experiments to reveal some of the universe’s deepest secrets.
