Document Type : Original Article
Authors
1 university of tabriz
2 university of tabriz ،Faculty of Physics
Abstract
In this paper, quantum thermal entanglement in a three qubit XY spin chain in a non homogenuous magnetic field is investigated and the amount of entanglement between the adjacent and non-adjacent qubits is measured by the concurrence criteria. Indeed, the dependence of the thermal entanglement on the controllable variables B (magnetic field), temperature T and the amount of heterogeneity b is investigated. The results of the paper shows that the thermal entanglement is decreased by increasing all three parameters B, T and b. Moreover, by controlling the mentioned parameters one can change the thermal entanglement between non-adjacent spins, c(ρ_13), so that its value get a bigger amount with respect to the thermal entanglement of the adjacent spins, i.e. c(ρ_12) and c(ρ_23). Finally, changes of the thermal entanglement between the spins with respect to the temperature has been compared with the time evolution of the entanglements between the corresponding qubits.
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