Work, entropy production, and thermodynamics of information under\n protocol constraints

Abstract

In many real-world situations, there are constraints on the ways in which a\nphysical system can be manipulated. We investigate the entropy production (EP)\nand extractable work involved in bringing a system from some initial\ndistribution $p$ to some final distribution $p'$, given that the set of master\nequations available to the driving protocol obeys some constraints. We first\nderive general bounds on EP and extractable work, as well as a decomposition of\nthe nonequilibrium free energy into an "accessible free energy" (which can be\nextracted as work, given a set of constraints) and an "inaccessible free\nenergy" (which must be dissipated as EP). In a similar vein, we consider the\nthermodynamics of information in the presence of constraints, and decompose the\ninformation acquired in a measurement into "accessible" and "inaccessible"\ncomponents. This decomposition allows us to consider the thermodynamic\nefficiency of different measurements of the same system, given a set of\nconstraints. We use our framework to analyze protocols subject to symmetry,\nmodularity, and coarse-grained constraints, and consider various examples\nincluding the Szilard box, the 2D Ising model, and a multi-particle flashing\nratchet.\n