7 hours ago
https://physicsworld.com/a/your-beer-can...mechanics/
INTRO: 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. “There was suggestive evidence from experiments, numerical simulations and analytical calculations that a physical system can’t be made to thermalize faster than some fundamental limit,” says Martí Perarnau-Llobet, a quantum scientist in the Quantum Information Group at the Autonomous University of Barcelona, Spain, and one of the paper’s authors.
Although the exact conditions under which thermalization is always guaranteed remain an unanswered puzzle, the researchers chose to focus on systems that do have this feature. To guarantee thermalization, Perarnau-Llobet and colleagues in Barcelona; Vienna, Austria; and Geneva, Switzerland came up with the mathematical notion of a thermalization machine. Given a quantum system in some initial state, this thermalization machine evolves it to a thermal state (that is, one that doesn’t spontaneously exchange net heat with its environment) at a particular well-defined temperature. In the previous example, the refrigerator and kettle would be considered thermalization machines, and your beer and water would be the systems... (MORE - details)
INTRO: 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. “There was suggestive evidence from experiments, numerical simulations and analytical calculations that a physical system can’t be made to thermalize faster than some fundamental limit,” says Martí Perarnau-Llobet, a quantum scientist in the Quantum Information Group at the Autonomous University of Barcelona, Spain, and one of the paper’s authors.
Although the exact conditions under which thermalization is always guaranteed remain an unanswered puzzle, the researchers chose to focus on systems that do have this feature. To guarantee thermalization, Perarnau-Llobet and colleagues in Barcelona; Vienna, Austria; and Geneva, Switzerland came up with the mathematical notion of a thermalization machine. Given a quantum system in some initial state, this thermalization machine evolves it to a thermal state (that is, one that doesn’t spontaneously exchange net heat with its environment) at a particular well-defined temperature. In the previous example, the refrigerator and kettle would be considered thermalization machines, and your beer and water would be the systems... (MORE - details)