Geometric Optimization of Nonequilibrium Adiabatic Thermal Machines and Implementation in a Qubit System

We adopt a geometric approach to describe the performance of adiabatic quantum machines, operating under slow time-dependent driving and in contact two or more reservoirs with temperature bias during all cycle. show that problem optimizing power generation heat engine efficiency both refrigerator operational modes is reduced an isoperimetric non-trivial underlying metrics curvature. This corresponds maximization ratio between area enclosed by closed curve its corresponding length. illustrate this procedure qubit coupled as thermal machine means protocol.