Figure 2.

Alternatively, our model can illustrate a non-autonomous device operated via feedback control by an external agent. (a) In the engine mode, which resembles Szilard’s thought experiment [35], the agent measures each incoming memory bit and switches a gate accordingly. When these measurements are accurate, the procedure induces a bias toward counter-clockwise rotation that can be harnessed to lift a small mass against gravity; (b) If the mass is large and falls against gravity, the energy that is released can be used to write a sequence chosen by the agent, onto the outgoing bit stream. In this mode, the agent does not measure the incoming bits, but rather manipulates the gate to encode the desired sequence.