Temperature gets a new definition using a quantum device
The main part of the new set-up for cooling and trapping rubidium atoms Tomasz Kawalec CC BY-SA 4.0 A better, more reliable definition of temperature could come from a quantum device full of giant atoms. While some countries measure temperatures in Celsius and others use Fahrenheit, physicists everywhere use a unit called kelvin. Zero kelvin denotes the absolute coldest temperature allowed by the known laws of physics, so kelvin is said to measure “absolute temperature”. In practice, however, making sure that when you measure a single kelvin, it really is a single kelvin is a laborious process. “If you want to make an absolute temperature measurement, you buy a commercial temperature sensor, which was calibrated by another commercial temperature sensor, which was calibrated by another commercial temperature sensor, and so on. And one of those sensors was, at some point, sent to the National Institute of Standards [and Technology],” says Noah Schlossberger at NIST in Colorado. He and his colleagues have now built a device that uses quantum effects to measure kelvin, which researchers could …
