Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field a...Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski-Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski-Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski-Moriya interaction is considered in a nonuniform magnetic field.展开更多
The thermal entanglement of a three-qubit Heisenberg chain under a nonuniform magnetic field is studied. It is very interesting to note that the next nearest neighbor entanglement （NNNE） could be larger than the nea...The thermal entanglement of a three-qubit Heisenberg chain under a nonuniform magnetic field is studied. It is very interesting to note that the next nearest neighbor entanglement （NNNE） could be larger than the nearest neighbor entanglement （NNE）. We analyze the ground state entanglement, and give the conditions that NNNE is larger than NNE near zero temperature. Our results also show that the nonuniform field could induce the entanglement and improve the threshold temperature at certain parameter region.展开更多
文摘Pairwise thermal entanglement in a three-qubit Heisenberg XX model is investigated when a nonuniform mag- netic field and the Dzyaloshinski-Moriya interaction are included. We find that the nonuniform magnetic field and Dzyaloshinski-Moriya interaction are the more efficient control parameters for the increase of entanglement and critical temperature. For both the nearest neighbour sites and the next nearest neighbour sites, the magnetic field can induce entanglement to a certain extent and the Dzyaloshinski-Moriya interaction can enhance the entanglement to a stable value. The steady value of the nearest neighbour site entanglement C12 is larger than the next nearest neighbour site entanglement C13. An interesting phenomenon is that the entanglement curve of C12 appears a peak value when the Dzyaloshinski-Moriya interaction is considered in a nonuniform magnetic field.
基金the Natural Science Foundation of Liaoning Province under Grant No.20031073
文摘The thermal entanglement of a three-qubit Heisenberg chain under a nonuniform magnetic field is studied. It is very interesting to note that the next nearest neighbor entanglement （NNNE） could be larger than the nearest neighbor entanglement （NNE）. We analyze the ground state entanglement, and give the conditions that NNNE is larger than NNE near zero temperature. Our results also show that the nonuniform field could induce the entanglement and improve the threshold temperature at certain parameter region.
