If you put a bottle of beer in a big bathtub full of ice-cold water, it won’t be long before you can enjoy a cold beer. Physicists discovered how this works more than a hundred years ago. Heat exchange takes place through the glass bottle until equilibrium is reached.
However, there are other systems, especially quantum systems, that don’t find equilibrium. They resemble a hypothetical beer bottle in a bath of ice-cold water that doesn’t always and inevitably cool to the temperature of the bath water, but rather reaches different states depending on its own initial temperature. Until now, such systems have puzzled physicists. But Nicolò Defenu, a postdoc at the ETH Zurich Institute for Theoretical Physics, has now found a way to elegantly explain this behaviour.
Source: “On eternal imbalance”, Zurich ETH News
