Exploiting positive work and efficiency of quantum Otto engine based on two coupled two-level atomic systems: Local vs global approach

We developed a model of a quantum Otto engine using two dipole-coupled two-level atoms. Based on the platform, we focus on fundamental thermodynamic quantities, including heat absorption, release to heat baths, work done, and efficiency. The characteristic of the engine either for the case of identical as well as non-identical two two-level atoms is investigated under the influence of average frequency, frequency detuning, and coupling strength. The conditions for the efficiency to be higher than in the noninteracting case are found. A tighter upper bound for the efficiency is found, which is lower than the Carnot limit. The second law of thermodynamics holds all the while. Our findings represent a step forward in the design of quantum thermodynamic devices, which take advantage of quantum resources.