The entanglement properties of a one-dimensional chain of qubits coupled via nearest neighbor spin-spin interaction were investigated. The robustness of n-concurrences of ground states when the interaction is subject to a time-reversal antisymmetric magnetic field perturbation was studied. The n-concurrence for thermal mixed states was derived and a threshold temperature was computed below which the system has nonzero entanglement. It is observed that nearly maximal n-concurrences is achievable in the XX model with zero magnetic field for sufficiently small temperatures.
|Number of pages||12|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - Nov 2004|