Enhanced thermal entanglement in an anisotropic Heisenberg XYZ chain -: art. no. 024301

The thermal entanglement in the Heisenberg XYZ chain is investigated in the presence of an external magnetic field B. In the two-qubit system, the critical magnetic field B-c is increased by introducing the interaction of the z component of two neighboring spins J(z). This interaction not only improves the critical temperature T-c, but also enhances the entanglement for a particular fixed B. We also analyze the pairwise entanglement between nearest neighbors in three qubits. The pairwise entanglement, for a fixed T, can become strong by controlling B and J(z).