The Dynamics Of Quantum Correlations For Two-qubit System Interacting With Their Own Macroscopic Objects

Quantum entanglement, as a kind of non-local correlation, is one of the im-portant features in quantum mechanics distinguished from the classic mechanics. Quantum entanglement and quantum discord are two different kinds of measure-ment methods of quantum correlation. Both of them can serve as a kind of impor-tant physical resource applying in the field of quantum computation and quantum information and realize the surpass from quantum to classic. Quantum system in-evitably interacts with the environment, and in the different noise environment, the time evolution of quantum entanglement and quantum discord are also different. To study the dynamics of quantum entanglement and quantum discord in the presence of environmental process are important for us underatanding and applying them better.In this paper, we study the dynamics of the quantum correlation between two-qubit system after interaction with the macroscopic mediums and the two-qubit system we considered is two particles with spin-1/2 and the macroscopic mediums are two one-dimensional linear arrays of spins and they have the same length and position. The model we studied is a generalized version of the CH model and can be solved exatly. Macroscopic mediums exchanging energy with the particles in-duced decoherence. It found that:1. In the case of that the two qubits pass their own macroscopic medium synchronously:if the initial state of two-qubit composite system is Bell state, quantum entanglement and quantum discord decay asymptot-ically and quantum discord decays faster than entanglement; if the initial state of two-qubit composite system is the mixture of Bell states, the entanglement decays monotonically and suffer a sudden death later. However quantum discord still keep the initial value and then decay asymptotically.2. In the case of that the two qubits pass their own macroscopic medium out-synchronously:if the initial state of two-qubit composite system is Bell state, When one of the two particles begin-s interact with it corresponding macroscopic medium, entanglement and quantum discord begin to decrease with time; After both of two particles enter the mediums, entanglement and quantum discord decay faster than before; if the initial state of two-qubit composite system is the mixture of Bell states, when one of the two par- ticles enters the corresponding medium, the entanglement decays monotically and quantum discord first keeps the initial value and then decays monotically. When both of two particles enter their local medium, entanglement decrease more quickly until it becomes zero and quantum discord decays faster and faster.