Scientists at the National Institute of Standards and Technology (NIST) have developed a highly sensitive thermometer using atoms expanded to extreme energy levels, making them a thousand times larger than normal.
By monitoring how giant Rydberg atoms interact with heat in their environment, Noah Schlossberger and colleagues can measure temperature with remarkable accuracy. Image Credit: R. Jacobson/National Institute of Standards and Technology
By tracking how these oversized "Rydberg" atoms interact with heat in their surroundings, researchers can achieve exceptionally precise temperature measurements. This innovation could enhance temperature monitoring in fields ranging from quantum research to industrial manufacturing.
Unlike traditional thermometers, a Rydberg thermometer does not require factory calibration because it operates based on fundamental quantum physics principles. These principles ensure precise measurements that are directly traceable to international standards.
We are essentially creating a thermometer that can provide accurate temperature readings without the usual calibrations that current thermometers require.
Noah Schlossberger, Postdoctoral Researcher, National Institute of Standards and Technology
Revolutionizing Temperature Measurement
The research, published in Physical Review Research, marks the first successful temperature measurement using Rydberg atoms. To construct this thermometer, researchers filled a vacuum chamber with a gas of rubidium atoms and used lasers and magnetic fields to trap and cool them to nearly absolute zero, around 0.5 millikelvin. At this temperature, the atoms were nearly motionless. Using lasers, scientists then excited the atoms' outermost electrons to high-energy orbits, enlarging them roughly 1,000 times compared to standard rubidium atoms.
Rydberg atoms are uniquely sensitive to external influences because their outermost electrons are far from the atomic core. This makes them particularly responsive to electric fields and blackbody radiation—the heat emitted by nearby objects. As blackbody radiation increases, electrons in Rydberg atoms transition to even higher energy states. Since rising temperatures amplify this effect, researchers can determine temperature by tracking these energy shifts over time.
This method enables the detection of even minute temperature fluctuations. While other quantum thermometers exist, Rydberg thermometers stand out because they can measure environmental temperatures ranging from 0 to 100 degrees Celsius without direct contact with the object being measured.
Beyond its immediate applications, this breakthrough holds significant promise for atomic clocks, which are highly sensitive to temperature fluctuations.
Atomic clocks are exceptionally sensitive to temperature changes, which can cause small errors in their measurements. We are hopeful this new technology could help make our atomic clocks even more accurate.
Chris Holloway, Research Scientist, National Institute of Standards and Technology
The potential applications extend far beyond precision science. From spacecraft to advanced manufacturing plants, environments that demand highly sensitive temperature readings could benefit from this innovation.
With this development, NIST continues to push the boundaries of scientific discovery.
This method opens a door to a world where temperature measurements are as reliable as the fundamental constants of nature. It is an exciting step forward for quantum sensing technology.
Chris Holloway, Research Scientist, National Institute of Standards and Technology
Journal Reference:
Schlossberger, N., et al. (2025) Primary quantum thermometry of mm-wave blackbody radiation via induced state transfer in Rydberg states of cold atoms. Physical Review Research. doi.org/10.1103/physrevresearch.7.l012020.