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A Thermometer in Diamond Dust ✛ ✎

Original: "Microkelvin resolution thermometry at the nanometre scale"
· Jack W. Hart, Soham Pal, Julien R. E. Roth, Katie Ninham, Abbie H. Aleksandrova, Xander Peetroons, Soumen Mandal, Oliver A. Williams, Gavin W. Morley, Mete Atature, Helena S. Knowles
arXiv:2609.04907v1 · 2026-09-04 · arXiv non-exclusive · independent analysis · 1 min
Quantum Physics Applied Physics Instrumentation and Detectors
A diamond speck with two defects senses heat a thousand times more accurately than an ordinary thermometer.

Imagine a speck of diamond so small you couldn't see it without a microscope. Inside it sit two defects, spots where a carbon atom is replaced by a nitrogen atom, with a vacancy nearby. These defects behave like tiny magnetic needles: when you hit them with a microwave pulse, they start to oscillate.

The oscillation frequency depends on temperature: warmer means faster oscillations, cooler means slower. That turns a defect into a thermometer.

Previously, such diamond thermometers were imprecise and couldn't detect the heat of a single cell. Now scientists have figured out how to make two defects work together, producing a stronger signal. They measured how the diamond heated up under a laser beam and saw a temperature jump when they mixed two liquids.

This thermometer can be placed inside a living cell to find out which parts are warmer. It can also be used to check how much heat a tiny catalyst particle releases during a chemical reaction. A thermometer in diamond dust opens a door to a world where temperature changes by millionths of a degree.

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A nanodiamond with two NV centers gives 30% better sensitivity than one with a single center, simply because there are twice as many photons and the coherence doesn't suffer.

\eta = \delta T \sqrt{t}
Minimum temperature change multiplied by the square root of measurement time
S(\tau) = C_{TE} \cos(\omega \tau) \exp\left[-\left(\frac{\tau}{T_{TE}}\right)^n\right]
Oscillating signal with exponential decay, whose frequency depends on temperature
Concepts
nv center sensing diamond defect sensing nanoscale temperature measurement diamond nv center millikelvin liquid nitrogen temperature cryogenic microwave measurement quantum thermometer sensitivity threshold thermometer nanophotonic device niobium nitride niobium aluminum nitride thermal camera thin film thermal management sensitivity heat transfer nanoscale accelerometer