Thermal Entangled Quantum Heat Engine Working with a Three-Qubit Heisenberg XX Model

Based on a three-qubit isotropic Heisenberg XX model with a constant external magnetic field, we construct an entangled quantum heat engine (QHE). The expressions for several thermodynamic quantities such as the heat transferred, the work and the efficiency are derived. Moreover, the influence of the entanglement on the thermodynamic quantities is investigated analytically and numerically. Several interesting features of the variation of the heat transferred, the work and the efficiency with the concurrences of the thermal entanglement of two different thermal equilibrium states in zero and nonzero magnetic fields are obtained. At last, we discussed the maximum efficiency of the QHE.