Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Acta Physica Sinica

Investigation of quantum discord for two-spin system

Wang Dan-Qin, He Chuang-Chuang

Published Jan 1, 2015• 1 citation
Publisher

Abstract

By adopting the concept of the geometric measure of quantum discord, we explore the property of quantum correlation in the two-spin Heisenberg model, gain the analytic expression of quantum discord in the general case, and discuss the influences of the coupling constant, temperature, the intensity of the external magnetic field on magnitude of the quantum correlation. The corresponding scheme of tuning quantum correlation is also given in this paper. In addition, we find that quantum discord has a sudden transition in the lower temperature. Results show that adjusting systematic parameters, which are temperature, coupling strength, magnetic field intensity, etc, is an effective way to control the value of quantum correlation in the double spin Heisenberg model system. This provides a certain reference and significant guidance for the precise control of quantum discord and realizing the teleportation of quantum state and the design of quantum logic gates.

DOI
10.7498/aps.64.043403

Related papers

Thermal Quantum Discord and Super Quantum Discord Teleportation Via a Two-Qubit Spin-Squeezing Model

Sodeif Ahadpour, Фороузан Мирмасоуди

We study thermal quantum correlations (quantum discord and super quantum discord) in a two-spin model in an external magnetic field and obtain relations between them and entanglement. We study their dependence on the magnetic field, the strength of the spin squeezing, and the temperature in detail. One interesting result is that when the entanglement suddenly disappears, quantum correlations still survive. We study thermal quantum teleportation in the framework of this model. The main goal is investigating the possibility of increasing the thermal quantum correlations of a teleported state in the presence of a magnetic field, strength of the spin squeezing, and temperature. We note that teleportation of quantum discord and super quantum discord can be realized over a larger temperature range than teleportation of entanglement. Our results show that quantum discord and super quantum discord can be a suitable measure for controlling quantum teleportation with fidelity. Moreover, the presence of entangled states is unnecessary for the exchange of quantum information.

Theoretical and Mathematical Physics•Apr 1, 2018•10 citations

Quantum Discord Behavior about Two-Qubit Heisenberg XYZ Model with Decoherence

Le Song, Guo-Hui Yang

We investigate the properties of quantum discord dynamics of a two-qubit Heisenberg XYZ system which is influenced by the environmental decoherence under an external nonuniform magnetic field. It shows that the influence of the parameters on the system heavily rely on the selection of the initial states. One point shows that the environmental decoherence cannot entirely destroy the quantum correlation, and properly controlling the parameters can inhibit the decoherence. Moreover, it presents that the inhomogeneous magnetic field cannot affect the steady quantum discord (QD), while the uniform magnetic field and the anisotropy coupling constant will change the steady QD. These investigations imply that one can obtain larger steady QD values by reasonably adjusting parameters on quantum correlation in solid state systems.

Chinese Physics Letters•Mar 1, 2014•3 citations

Thermal geometric discords in a two-qubit Heisenberg XY model

Fan Hong-Rui, Yuan Ya-Li, Xi-Wen Hou

We study the influences of the external magnetic field, temperature, and coupling parameter on the thermal quantum correlation in a two-qubit Heisenberg XY model, where the correlation is described in terms of two modified geometric discords and concurrence. It is shown that those three quantities behave similarly in the regions of lower temperature and weak magnetic field. However, the two geometric discords are more robust against temperature and magnetic field than the concurrence. Moreover, two geometric discords exhibit different behaviors under suitable conditions, that is, one discord increases as the magnetic field rises whereas the other discord decreases. In particular, the discord reveals the phenomenon of sudden change, while neither of other discord and concurrence displays such a phenomenon.

Acta Physica Sinica•Jan 1, 2016•0 citations

Effect of Spin-Orbit Interaction and Input State on Quantum Discord and Teleportation of Two-Qubit Heisenberg Systems

Meng Qin, Xiao-Yue Zhai, Xuan Chen +3 more

We study the quantum discord and teleportation of a two-qubit Heisenberg XXX chain with spin-orbit interaction. The analytical expressions of quantum discord, output state quantum discord and fidelity are obtained for this model. The classical correlation, quantum correlation and entanglement of this system depending on coupling interaction, spin-orbit interaction and temperature are investigated in detail. It is found that the quantum discord exists for the ferromagnetic case, but entanglement is zero under the same condition. We can obtain fidelity better than any classical communication protocol for the antiferromagnetic case. The robustness of quantum discord against the temperature is helpful for the realization of quantum computation.

Chinese Physics Letters•Mar 1, 2012•3 citations

Properties of quantum correlations in the Yang-Baxter spin-1/2 chain mode

Lidan Gou, Xiaoqian Wang

Quantum correlations among different parts of a composite quantum system are the fundamental resource of several applications in quantum information. In general, quantum discord can measure quantum correlations. In that way, the quantum correlations in the Yang-Baxter spin-1/2 chain mode are investigated. In the second part of the paper, the Yang-Baxter spin-1/2 chain modes are constructed from the Yang-Baxter equation. First, we analyze the two matrix representations of Temperly-Lieb algebra. Second, the two solutions of the Yang-Baxter equation are generated using the Yang-Baxterization. Finally, we can change the usual two-particle spin-1/2 chain to the Yang-Baxter spin-1/2 chain modes by means of the unitary Yang-Baxter matrix-R. In the third part, the density matrices of the two chain modes are generated in the thermal equilibrium state in a canonical ensemble. According to the definition of the geometric measure of quantum discord, the analytical expressions of the geometric measure of quantum discord, in the temperature and the external magnetic field, are obtained for the Yang-Baxter spin-1/2 chain modes. When the temperature and the magnetic field intensity increase, the geometric measure of quantum discord decreases. Under the specific conditions, the result of the second chain mode is similar to that of the first one. Then we obtain the numerical results of quantum discord, the geometric measure of quantum discord, and concurrence. It is found that the concurrence can quickly decrease to the value of zero when the temperature is greater than the value of one. At the same time, quantum discord and the geometric measure of quantum discord are not of the value of zero. Thus the quantum discord and the geometric measure of quantum discord can go beyond the concept of entanglement and obtain the “quantumness” of the correlations between the two parts of a system for the Yang-Baxter spin-1/2 chain modes. They are very good quantum resources for quantum information and quantum computing.

Acta Physica Sinica•Jan 1, 2015•1 citation

Dynamics of quantum correlations in four-qubit XXZ Heisenberg model with external magnetic field

Su-Bok Ri, Gwang-Jin Kim, Ha Kim +1 more

In this paper we argue about the quantum correlation (quantum entanglement and geometric quantum discord) in four-qubit XXZ Heisenberg Model. Here, the influence of uniform magnetic field on the dynamics of quantum correlation in cases of the antiferromagnetism has been mainly investigated. According to the results, it has been illustrated that the role of the uniform magnetic field on the dynamics of quantum correlation depends on the selection of the initial state. Furthermore, geometric quantum discord exhibits greater robustness compared to quantum entanglement. Also results show that the max values of quantum correlations decrease and the duration of quantum entanglement sudden death gets longer as purity parameter decreases, and that exchange interaction can substantially make an effect on the dynamics of the quantum correlation.

Results in Physics•May 1, 2025•0 citations
By adopting the concept of the geometric measure of quantum discord, we explore the property of quantum correlation in the two-spin Heisenberg model, gain the analytic expression of quantum discord in the general case, and discuss the influences of the coupling constant, temperature, the intensity of the external magnetic field on magnitude of the quantum correlation. The corresponding scheme of tuning quantum correlation is also given in this paper. In addition, we find that quantum discord has a sudden transition in the lower temperature. Results show that adjusting systematic parameters, which are temperature, coupling strength, magnetic field intensity, etc, is an effective way to control the value of quantum correlation in the double spin Heisenberg model system. This provides a certain reference and significant guidance for the precise control of quantum discord and realizing the teleportation of quantum state and the design of quantum logic gates.
We study thermal quantum correlations (quantum discord and super quantum discord) in a two-spin model in an external magnetic field and obtain relations between them and entanglement. We study their dependence on the magnetic field, the strength of the spin squeezing, and the temperature in detail. One interesting result is that when the entanglement suddenly disappears, quantum correlations still survive. We study thermal quantum teleportation in the framework of this model. The main goal is investigating the possibility of increasing the thermal quantum correlations of a teleported state in the presence of a magnetic field, strength of the spin squeezing, and temperature. We note that teleportation of quantum discord and super quantum discord can be realized over a larger temperature range than teleportation of entanglement. Our results show that quantum discord and super quantum discord can be a suitable measure for controlling quantum teleportation with fidelity. Moreover, the presence of entangled states is unnecessary for the exchange of quantum information.
We investigate the properties of quantum discord dynamics of a two-qubit Heisenberg XYZ system which is influenced by the environmental decoherence under an external nonuniform magnetic field. It shows that the influence of the parameters on the system heavily rely on the selection of the initial states. One point shows that the environmental decoherence cannot entirely destroy the quantum correlation, and properly controlling the parameters can inhibit the decoherence. Moreover, it presents that the inhomogeneous magnetic field cannot affect the steady quantum discord (QD), while the uniform magnetic field and the anisotropy coupling constant will change the steady QD. These investigations imply that one can obtain larger steady QD values by reasonably adjusting parameters on quantum correlation in solid state systems.
We study the influences of the external magnetic field, temperature, and coupling parameter on the thermal quantum correlation in a two-qubit Heisenberg XY model, where the correlation is described in terms of two modified geometric discords and concurrence. It is shown that those three quantities behave similarly in the regions of lower temperature and weak magnetic field. However, the two geometric discords are more robust against temperature and magnetic field than the concurrence. Moreover, two geometric discords exhibit different behaviors under suitable conditions, that is, one discord increases as the magnetic field rises whereas the other discord decreases. In particular, the discord reveals the phenomenon of sudden change, while neither of other discord and concurrence displays such a phenomenon.
We study the quantum discord and teleportation of a two-qubit Heisenberg XXX chain with spin-orbit interaction. The analytical expressions of quantum discord, output state quantum discord and fidelity are obtained for this model. The classical correlation, quantum correlation and entanglement of this system depending on coupling interaction, spin-orbit interaction and temperature are investigated in detail. It is found that the quantum discord exists for the ferromagnetic case, but entanglement is zero under the same condition. We can obtain fidelity better than any classical communication protocol for the antiferromagnetic case. The robustness of quantum discord against the temperature is helpful for the realization of quantum computation.
Quantum correlations among different parts of a composite quantum system are the fundamental resource of several applications in quantum information. In general, quantum discord can measure quantum correlations. In that way, the quantum correlations in the Yang-Baxter spin-1/2 chain mode are investigated. In the second part of the paper, the Yang-Baxter spin-1/2 chain modes are constructed from the Yang-Baxter equation. First, we analyze the two matrix representations of Temperly-Lieb algebra. Second, the two solutions of the Yang-Baxter equation are generated using the Yang-Baxterization. Finally, we can change the usual two-particle spin-1/2 chain to the Yang-Baxter spin-1/2 chain modes by means of the unitary Yang-Baxter matrix-R. In the third part, the density matrices of the two chain modes are generated in the thermal equilibrium state in a canonical ensemble. According to the definition of the geometric measure of quantum discord, the analytical expressions of the geometric measure of quantum discord, in the temperature and the external magnetic field, are obtained for the Yang-Baxter spin-1/2 chain modes. When the temperature and the magnetic field intensity increase, the geometric measure of quantum discord decreases. Under the specific conditions, the result of the second chain mode is similar to that of the first one. Then we obtain the numerical results of quantum discord, the geometric measure of quantum discord, and concurrence. It is found that the concurrence can quickly decrease to the value of zero when the temperature is greater than the value of one. At the same time, quantum discord and the geometric measure of quantum discord are not of the value of zero. Thus the quantum discord and the geometric measure of quantum discord can go beyond the concept of entanglement and obtain the “quantumness” of the correlations between the two parts of a system for the Yang-Baxter spin-1/2 chain modes. They are very good quantum resources for quantum information and quantum computing.
In this paper we argue about the quantum correlation (quantum entanglement and geometric quantum discord) in four-qubit XXZ Heisenberg Model. Here, the influence of uniform magnetic field on the dynamics of quantum correlation in cases of the antiferromagnetism has been mainly investigated. According to the results, it has been illustrated that the role of the uniform magnetic field on the dynamics of quantum correlation depends on the selection of the initial state. Furthermore, geometric quantum discord exhibits greater robustness compared to quantum entanglement. Also results show that the max values of quantum correlations decrease and the duration of quantum entanglement sudden death gets longer as purity parameter decreases, and that exchange interaction can substantially make an effect on the dynamics of the quantum correlation.