Correlated catalyst in quantum thermodynamics

In this short review article, we present recent progress in quantum thermodynamics in the framework with a correlated catalyst. We examine two key properties of thermal operations, the Gibbs preserving property and the covariant property. The state convertibility of a Gibbs preserving operation is fully characterized by the second law of thermodynamics with the nonequilibrium free energy. The state convertibility of a covariant operation is shown to be free as long as an initial state has finite coherence. We finally show that these two findings can be combined in the enhanced thermal operation (covariant Gibbs-preserving operation).