Fig. 3.

Illustration of the forward process: a system in equilibrium state $p_{\mathrm{eq}}$ with mean value at $x=0$ is kicked at a time $t=0$ with magnitude $x_0$ to a state $p_{\mathrm{kick}}$ far from equilibrium, followed by a dissipative process back to equilibrium. x is a set of reduced variables which captures the information on the work. The arrows connecting $p_{\mathrm{kick}}$ at time $t=0,p_t$ at $t>0$, and $p_{\mathrm{eq}}$ at $t\to \infty$ indicate the tube of trajectories, which is “thin” for macroscopic systems as deviations from the mean values $x\left(t\right)$ are small