Indian team’s breakthrough set to supercharge atomic clock accuracy

A team of researchers at the Raman Research Institute (RRI) has made a significant advancement in quantum magnetometry, potentially improving the precision of atomic clocks and magnetometers used in navigation, telecommunication, and aviation.
Quantum magnetometry is a technique used to measure extremely small magnetic fields with high precision, leveraging principles of quantum mechanics. It often involves using quantum systems like atoms, ions, or superconducting circuits, which are highly sensitive to magnetic field changes.
Atomic clocks are highly precise timekeeping device that uses the vibrations or transitions of atoms to measure time. GPS satellites rely on atomic clocks to synchronize signals and provide accurate location data. GPS satellites rely on atomic clocks to synchronize signals and provide accurate location data.
The scientists leveraged the Doppler effect to achieve a tenfold enhancement in magnetic field response while performing quantum magnetometry on thermal rubidium atoms.
This breakthrough was accomplished using Rydberg Electromagnetically Induced Transparency (EIT) in a room-temperature environment.

The new system makes the system more practical for real-world applications. (Photo: Getty)

Rydberg atoms, which are excited atoms with electrons at very high energy levels, were detected using Rydberg EIT. The team observed an enhanced response to magnetic fields when the Rydberg EIT was configured in an unconventional way, where the Doppler shift was not compensated.
Dr. Sanjukta Roy, Head of Quantum Optics with Rydberg Atoms Lab at RRI, explained, “It is the Doppler shift which causes a larger response of the Rydberg EIT signal to an externally applied magnetic field.”
Typically, the Doppler effect is considered detrimental to sensing. However, the researchers successfully harnessed this quantum effect at room temperature, turning a potential disadvantage into a benefit.
The study, published in the New Journal of Physics, demonstrates that this technique can detect weak magnetic fields without requiring cryogenic cooling or ultra-high vacuum conditions. This makes the system more practical for real-world applications.
Shovan Kanti Barik, lead author of the paper, noted, “Magnetic fields alter the energy levels. In its presence, the energy levels get shifted by different amounts, producing multiple transmission peaks whose separation can be used to measure the magnetic field.”
This Doppler-enhanced quantum magnetometry has potential applications in various fields, including geophysics, brain activity detection, mineralization, space exploration, and archaeology.
The advancement could lead to more precise and robust atomic clocks and magnetometers, enhancing the accuracy of critical systems relying on precise timekeeping and magnetic field measurements.