We investigate heat engines whose working substance is made of two coupled qubits performing a generalized Otto cycle by varying their applied magnetic field or their interaction strength during the compression and expansion strokes. During the heating and cooling strokes, the two qubits are coupled to local and common environments that are not necessarily at equilibrium. We find instances of quantum engines coupled to nonequilibrium common environments exhibiting nontrivial connections to quantum correlations as witnessed by a monotonic dependence of the work produced on quantum discord and entanglement.
In this paper, the moderately long-time behaviours of the correlation functions for two charged coupled harmonic oscillators connected to a common heat bath are analyzed in the presence of a magnetic field via the Quantum Langevin dynamics. Interestingly it is seen that at long times the correlation functions at
T→0 exhibit a power law decay with the coefficients of the power laws being completely different for the two masses, affecting the overall dynamics of the coupled system. The effect of the bath-induced force on mass m1 mediated by the interaction of m2 with the common heat bath is studied and the results are highlighted in the presence of an external magnetic field. It is shown that the effect of cyclotron frequency increases the correlation functions at an instant of time, lowering the rate of temporal decay of the correlation functions. The results in the absence of a magnetic field are also presented, which are extremely important for investigating the movements of the atoms in protein molecules at low temperatures.