Based on a two-qubit Heisenberg XY model, we construct a four-level entangled quantum heat engine (QHE). It is an interesting quantum Otto cycle where the exchange constant is fixed and only the magnetic field is varied during the adiabatic steps. The expressions for several thermodynamic...

Based on independent studies, this paper focuses on the significant discrepancy of 15GW between the installed onshore wind generation capacity and what has been actually connected to the power network to reveal the challenges in meeting the Chinese renewable energy target. The recent accidents...