The Studies On Einstein-Podolsky-Rosen Steering Decoherence

EPR quantum steering is an important form of quantum correlation between quantum entanglement and Bell nonlocality.It is an important resource in quantum information and plays an irreplaceable role in many fields such as quantum communication,quantum computing and quantum cryptography.However,in the actual quantum information task,the quantum system and its surrounding environment will inevitably couple with each other,which will lead to the rapid decline of the quantum non-local correlation of the system,the so-called quantum decoherence phenomenon.The application of quantum correlation has been seriously hindered by this.Therefore,it is of great significance to study the dynamic characteristics of EPR quantum steering in open systems.The main work of this article can be divided into two parts:One one hand,the dynamic behavior of EPR steering of the two-qubit system measured by the EPR quantum steering robustness under the XY spin chain model is studied.The results show that the steering robustness is significantly suppressed when the environment undergoes a quantum phase transition.The scaling behavior for the dynamics of EPR steering is also revealed and analyzed around the critical point.Furthermore,we find that steering robustness power(i.e.the average value of steering robustness within a certain time)can indicate the quantum criticality of the environment directly.Besides,the degree of mixing of the initial state of the system in the spin chain environment has a direct impact on the robustness of EPR steering.One the other hand,the article discusses the EPR quantum steering dynamic behavior of the Bell diagonal state and two qubit X-type state coupled with independent local noise channels,i.e.,bit flip channel,phase flip channel,bit-phase flip channel and generalized amplitude damping.The study found that the degree of mixing of the initial states of the quantum states and different types of noise channels will directly affect the robustness of EPR steering.The higher the degree of mixing,the worse the robustness of EPR steering.The robustness of EPR steering of a pure state is the best.In addition,in the situation where the one-sided noise channel is coupled with any X-type two-qubit state,the inherent asymmetry of EPR quantum steering can be used to determine the location of the one-sided noise channel.