Researchers from the Autonomous University of Barcelona and the University of Nottingham have invented a thermometer that can measure the smallest possible fluctuation in temperature.

"Finding a nanothermometer sensitive enough at this scale is a great step forward in the field of nanotechnology, with applications in biology, chemistry, physics, and even in the diagnosis and treatment of diseases," the researchers said.

The researchers studied the sensitivity of thermometers created with a handful of atoms, small enough to be capable of showing typical quantum-style behaviour. 

This device could provide an estimation of the temperature with a never before seen precision.

The physicists were searching for the maximum precision which could be achieved in a real situation.

In the research, they also observed that these thermometers could maintain a constant sensitivity in a wide range of temperatures by sacrificing some of their precision.

The finding was published in the journal Physical Review Letters.