Detector-defined coarse-graining, exact lumpability, and hidden entropy production

Replication code for: "Detector-defined coarse-graining, exact lumpability, and hidden entropy production" Craig S. Wright, University of Exeter Generates Figures 1 and 2 from the analytic expressions in Section VI. Figure 1: Detector-hidden free energy D(rho_t || C(rho_t)) / ln 2 vs dimensionless time gamma*t. Eq. (12): D = ln 2 - h((1 + eta_t)/2), eta_t = exp(-gamma*t). Figure 2: Entropy production Sigma(0 -> t) / ln 2 vs dimensionless time gamma*t. Eq. (13): Sigma = D(rho_0 || C(rho_0)) - D(rho_t || C(rho_t)) = h((1 + eta_t)/2). Bound is exactly saturated: Sigma = Delta D at all t. All quantities are analytic; no numerical simulation is involved. Requirements: numpy, matplotlib Usage: python3 generate_figures.py Output: fig1.pdf, fig2.pdf