Maxwell’s demon can extract work from a single heat reservoir at a cost of spin angular momentum. In step (a), the demon has no memory and the gas in the heat reservoir is in thermal equilibrium. In step (b), the demon divides the reservoir in two, trapping the fastest moving molecules on the right side, and uses a heat engine operating between the two partitions to extract work. In step (c), the demon's memory is erased using a spin reservoir and the two partitions are allowed to return to equilibrium. Image credit: Joan A. Vaccaro, et al. Fig. 1. ©2011 Royal Society.
Until now, scientists have thought that the process of erasing information requires energy. But a new study shows that, theoretically, information can be erased without using any energy at all. Instead, the cost of erasure can be paid in terms of another conserved quantity, such as spin angular momentum.
To read the rest of the article, click here.