Hold my beer: A bottle of beer kept in a refrigerator to cool down. The fridge can be thought of as the thermalization machine and the bottle of beer as the system. (Courtesy: iStock/kurgu128)

How fast can a kettle boil water for your cup of tea, or a refrigerator cool down a bottle of beer? The answer depends on the details of the machines, but according to new work published in Nature Physics , the minimum wait time does not. Instead, it’s quantum mechanics that imposes a limit on how fast something can thermalize to a particular temperature.

Objects thermalize, or reach a state of thermal equilibrium, when they no longer exchange any net heat with their environment. Physicists already suspected that this process couldn’t happen arbitrarily quickly.…