Almost thermal operations: inhomogeneous reservoirs

Understand

The resource theory of thermal operations explains the state transformations that are possible in a very specific thermodynamic setting: there is only one thermal bath, auxiliary systems can only be in corresponding thermal state (free states), and the interaction must commute with the free Hamiltonian (free operation).

• In this paper we study the mildest deviation: the reservoir particles are subject to inhomogeneities, either in the local temperature (introducing resource states) or in the local Hamiltonian (generating a resource operation).
• For small inhomogeneities, the two models generate the same channel and thus the same state transformations.
• However, their thermodynamics is significantly different when it comes to work generation or to the interpretation of the "second laws of thermal operations".