You’re hot and you’re cold

Typically, for everyday objects, a single point on the object might be expected to be at a single temperature. However, research by physicists at the University of Exeter suggests that, for small objects, the situation might be more complicated.

In the 1930s, Heisenberg and Bohr applied the uncertainty principle to the relationship between heat transfer and temperature. In order to precisely measure the temperature of an object, it has to be isolated from its surroundings. But measurement of temperature involves some contact with a measuring device which will cause uncertainty in the temperature reading.

Whilst a typical thermometer will display some uncertainty in its readings, one of the authors of the Exeter research, Henry Miller, argues that when measuring on the very small scale, a quantum thermometer has a different issue: “What we find is that because the thermometer no longer has a well-defined energy and is actually in a combination of different states at once, that this actually contributes to the uncertainty in the temperature that we can measure.” One interpretation of this claim is that an object might be considered to be at two temperatures at once.