Nonequilibrium Thermodynamics of a Superconducting Szilard Engine

We implement a Szilard engine that uses a 2-bit logical unit consisting of coupled quantum flux parametrons -- Josephson-junction superconducting circuits originally designed for quantum computing. Detailed simulations show that it is highly thermodynamically efficient while functioning as a Maxwell demon. The physically-calibrated design is targeted to direct experimental exploration. However, variations in Josephson junction fabrication introduce asymmetries that result in energy inefficiency and low operational fidelity. We provide a design solution that mitigates these practical challenges. The resulting platform is ideally suited to probe the thermodynamic foundations of information processing devices far from equilibrium.