Quantum heat engine efficiency of a small spin system with anisotropy

The rise of electronic devices lower than the nanoscale shifts the focus to quantum heat engines as they have improved features than their classical counterparts. In this work, the two-spin and three-spin systems using the Lipkin-Meshkov-Glick (LMG) model as the working substance of the heat engine are considered. The efficiency of the quantum heat engine comprised of two reversible isothermal processes and two isomagnetic processes with varying spin anisotropy is investigated.