Fig. 3.

Work and internal energy of the system. (A) Total extracted work during step 3 as a function of $\sqrt{\overline{n}}$, with $\overline{n}$ the number of photons in the demon memory. Symbols correspond to measurement of the battery, and solid lines result from simulations. Colors correspond to the same initial states of the system as in Fig. 2. (B) Symbols denote measured internal energy $U_S$ of the system at step 4 as a function of the amplitude ${\alpha }_{in}$ of the pulse at $f_D$ used in step 2 to encode information in the demon’s memory. Error bars are smaller than symbol size. Solid lines result from the full master equation and establish the conversion between ${\alpha }_{in}$ and $\sqrt{\overline{n}}$. An additional dark blue color corresponds to an initial temperature $T_S=T_S^0$. Dashed lines indicate $U_S$ after preparation step 1. The equality of extracted work (A) and change in $U_S$ (B) is highlighted by dashed arrows of identical lengths.