Thermodynamics with Correlations: Enhancing the Performance of Quantum Maxwell Demons
January 14, 2016
Adrian Chapman and Akimasa Miyake have recently published their paper in Physical Review E, demonstrating that a Maxwell demon can exploit correlations in its memory to enhance its thermodynamic performance over the demon which cannot. In this classic thought experiment, the demon uses information, rather than energy, to perform a thermodynamic task such as refrigeration. One example is realized by a demon who controls the door of a bipartite container filled with gas. Using a microscopic measuring device, the demon allows only faster molecules to one side while allowing only slower molecules to the other, apparently performing cooling for free. Only when one accounts for the inevitable energy cost of erasing the device’s memory does one see that this supposed perpetual motion machine is actually a refrigerator. This fact suggests that information has value in thermodynamics.