Implementation of a quantum Otto thermal machine using an XX spin chain model

Quantum thermal machine models are essential to understanding the thermodynamics of nanoscale systems. A quantum Otto thermal machine with a spin XX chain working substance was considered. The different working regimes was demonstrated for a chain of 10 spins by calculating the work and heat absorbed for one cycle. It was found that at high bath temperatures, the quantum Otto engine mainly operates as either accelerator or a heat engine, while at low bath temperatures it operates mainly as a heater.