(Phys.org) Physicists from Kaiserslautern and a colleague from Hanover have succeeded for the first time in using a single cesium atom as a sensor for ultracold temperatures. To determine the measured data, they used quantum states—the spin or angular momentum of the atom. Such sensors could be used in the future, for example, to investigate quantum systems without interference.
The special feature of the study was the high sensitivity of the measurement. In a typical measurement, it is necessary to bring the sensor into contact with the cold gas and wait until equilibrium is reached. The measuring system of the Kaiserslautern researchers has a sensitivity that is about 10 times higher than the fundamental quantum limit requires.
“This is the first time we have used a single atom as a sensor that uses quantum information and is significantly better than a classic sensor,” explains Professor Widera of Technische Universität Kaiserslautern (TUK).

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