Information processing, quantum or classical, relies on channels transforming multiple input states to different
corresponding outputs. Previous research has established bounds on the thermodynamic resources required for
such operations, but no protocols have been specified for their optimal implementation. For the insightful case
of ...
Information processing, quantum or classical, relies on channels transforming multiple input states to different
corresponding outputs. Previous research has established bounds on the thermodynamic resources required for
such operations, but no protocols have been specified for their optimal implementation. For the insightful case
of qubits, we here develop explicit protocols to transform two states in an energetically optimal manner. We first
prove conditions on the feasibility of carrying out such transformations at all, and then quantify the achievable
work extraction. Our results uncover a fundamental incompatibility between the thermodynamic ideal of slow,
quasistatic processes and the information-theoretic requirement to preserve distinguishability between different
possible output states.