Entanglement dynamics in a spin star system coupled weakly to a bosonic bath

Abstract

In the broad realm of applications of quantum thermodynamics, a non-unitary formulation of theory is particularly well suited for describing the evolution of an open quantum system. The robust framework upon which this formulation is established enfolds the nature of system and its environment. Based on this frame, we use Born–Markov approximation to derive a master equation for the density operator of a spin star configuration. With the help of Markovian master equation, we analyze how the reservoir’s temperature and the value of system–environment coupling act on the behavior of entanglement. In the absence of an environment interaction, maximally entangled quantum W states are induced by the coherent evolution of the system. On the other hand, it is found that the environment can boost the entanglement between the second neighbors across the entanglement between the first neighbors at times when quantum W states were going to happen. At the same time instants, it is shown that the entanglement follows a power-law decay consistent with $$0.5-b\gamma ^\alpha $$ , where $$\gamma $$ is the system–environment coupling strength and the exponent lies in the range $$0.5<\alpha <0.6$$ . In addition, by comparing between the role of $$\gamma $$ and the environment’s temperature, it is revealed that the entanglement is not as sensitive to the bath’s temperature as the system–environment coupling coefficient. Our results can stimulate both experimental and theoretical interests in exploring the dissipative role of environment on spin star structures in realistic situations and can open new perspectives for this field.