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We rigorously prove that the S = 1 / 2 anisotropic Heisenberg chain (XYZ chain) with next-nearest-neighbor interaction, which is anticipated to be non-integrable, is indeed non-integrable in the sense that this system has no nontrivial local conserved quantity. Our result covers some important models including the Majumdar–Ghosh model, the Shastry–Sutherland model, and many other zigzag spin chains as special cases. These models are shown to be non-integrable while they have some solvable energy eigenstates. In addition to this result, we provide a pedagogical review of the proof of non-integrability of the S = 1 / 2 XYZ chain with Z magnetic field, whose proof technique is employed in our result. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of two-spin nonlocality generation in a Heisenberg XXX chain with Dzyaloshinskii-Moriya (DM) and Kaplan-Shekhtman-Entin-Wohlman-Aharony (KSEA) interactions. We analyze the two-spin nonlocality dynamics by using uncertainty-induced nonlocality, maximal Bell function, and log-negativity. We demonstrate that a separable two-spin Heisenberg XXX chain state, induced by two-spin antiferromagnetic interaction as well as x-component of DM and KSEA interactions, could evolve to maximal two-spin nonlocality state. The ability of preserving the maximal uncertainty-induced nonlocality can be enhanced by increasing the coupling strength of the spin-spin interaction coupling. The hierarchy principle is maintained for the two-spin Bell nonlocality and log-negativity entanglement. The two-spin log-negativity dynamics exhibits the phenomena of sudden death and birth. The sudden-death phenomenon is due to the intrinsic decoherence, which also causes a reduction in the two-spin nonlocality. While the sudden-birth phenomenon is due to two-spin antiferromagnetic interaction as well as x-component of DM and KSEA interactions. The two-spin uncertainty-induced nonlocality is more robust, against the intrinsic decoherence, than the other types of the nonlocality. The results indicate that by boosting the two-spin antiferromagnetic interaction, the produced nonlocality (resulting from the DM and KSEA x-component interactions) can be shielded from the intrinsic decoherence effect. [ABSTRACT FROM AUTHOR]

This article explores the concurrence in a two-qubit Heisenberg XXX model with Dzyaloshinskii–Moriya (DM) and Kaplan–Shekhtman–Entin-Wohlman–Aharony (KSEA) interactions. The concurrence expression was developed using the physical variables connected with the chosen system. Our results indicate that the temperature, the spin coupling constant, the x-components of the DM and KSEA interactions may all play a role in determining the degree of intricacy between states. Additionally, these findings imply that the separability of states is obtained at high-temperature domains or by switching the spin coupling. In contrast, the entanglement of states may be achieved at low temperatures or by using high values of the x-components of the DM and KSEA parameters. Furthermore, the DM and KSEA interactions have an identical effect on the concurrence behaviors at high temperatures. [ABSTRACT FROM AUTHOR]

We study the effect of magnetic field and temperature on the amount of coherence of two arbitrary spins in the Heisenberg chain. While increasing temperature always leads to lowering the value of this coherence, in case of magnetic field, it increases the coherence up to a certain value and ultimately it decreases its value to zero. Moreover we find that in a Heisenberg chain, at any temperature the coherence between spins vanishes with distance exponentially with a characteristic distance given by ∼ J k T . The effect of magnetic field is only to set the magnitude of this coherence. [ABSTRACT FROM AUTHOR]

Entanglement teleportation via two spins coupled to each other by one axis twisting spin squeezing interaction is investigated. We mainly concentrate on the properties of the channel entanglement, the output entanglement and the teleportation fidelity. It shows that the output entanglement increases linearly with increasing the value of the input entanglement. With the increasing of T, the teleportated entanglement increases sharply from zero to a maximum value and then decreases slowly to zero when the temperature is improved to one threshold value of T, and the threshold value of T increases with the increasing of the input entanglement. When enlarging the external magnetic, F firstly decreases quickly to a minimum value as the critical magnetic field Ω is reached, then it increases abruptly to a maximum value and finally it will be a certain value. Besides, the critical external magnetic Ω increases when μ is larger. For Ω<Ω the value of the average fidelity increases with the increasing of μ, but for Ω>Ω the value of it decreases from a maximum value. The influence of T on the average fidelity is similar with μ. [ABSTRACT FROM AUTHOR]

By introducing the nonuniform magnetic field, we investigate the entanglement teleportation via two-qubit Heisenberg chain. We show that for ferromagnetic chain, the opposite direction magnetic field on the two-qubit chain can excite the teleported entanglement C out, while the uniform magnetic field can not do it. The effect of the uniform magnetic field B and the nonuniform magnetic field b on the threshold temperature T c is also plotted. Our study on the average fidelity of this quantum channel system shows that the magnetic field in opposite direction can result in the ideal average fidelity no matter whether the chain is ferromagnetic or antiferromagnetic. [ABSTRACT FROM AUTHOR]

We investigated the quantum entanglement in spin-1 Heisenberg XY chain for two-spin-qutrit and multi-particle systems. As a measure of the entanglement, the negativity of this state was analyzed as a function of the temperature and the magnetic field. We gave some numerical results and discussed them in detail. We found that the negativity increases monotonously with the coupling constants | J 1| and | J 2|, and it showed a symmetry with respect to the point of J 1 = 0 and J 2 = 0. In addition to the above features, there is evidence that the critical temperature is independent of the length of the chain. [ABSTRACT FROM AUTHOR]