© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Journal of Sichuan University

The concurrence of quantum states of XXX models in a time-dependent arbitrary external field

Cheng Ji

Published Jan 1, 2008• 0 citations

Abstract

Based on algebraic dynamics and the concept of the concurrence of the entanglement,we investigate the evolutive properties of the TwoQubit entanglement that formed by Heisenberg XXX models under a time-dependent arbitrary external field.For this system,the property of the concurrence that is only dependent on the coupling constant J and total values of the external field is proved.Furthermore,we found that the thermal concurrence of the system under a static arbitrary external field is a function of the coupling constant J,temperature T and the magnitude of external field.

Related papers

Concurrence of Quantum States: Algebraic Dynamical Method Study XXX Models in a Time-Depending Random External Field

Chuan‐Ji Fu, Qinsheng Zhu, Wu Shao-Yi

Based on algebraic dynamics and the concept of the concurrence of the entanglement, we investigate the evolutive properties of the two-qubit entanglement that formed by Heisenberg XXX models under a time-depending external held. For this system, the property of the concurrence that is only dependent on the coupling constant J and total values of the external field is proved. Furthermore, we found that the thermal concurrence of the system under a static random external field is a function of the coupling constant J , temperature T , and the magnitude of external held.

Communications in Theoretical Physics•Jun 1, 2010•2 citations

THERMAL ENTANGLEMENT IN THE TWO-QUBIT HEISENBERG XYZ MODEL

Gustavo Rigolin

We study the entanglement of a two-qubit one-dimensional XYZ Heisenberg chain in thermal equilibrium at temperature T. We obtain an analytical expression for the concurrence of this system in terms of the parameters of the Hamiltonian and T. We show that depending on the relation among the coupling constants, it is possible to increase the amount of entanglement of the system by increasing its anisotropy. We also show numerically that for all sets of the coupling constants entanglement is a monotonically decreasing function of the temperature T, proving that we must have at least an external magnetic field in the z-direction to obtain a behavior where entanglement increases with T.

arXiv:quant-ph/0311185•International Journal of Quantum Information•Aug 30, 2004•48 citations

Entanglement evolution of two-coupled spins in a time-dependent rotating magnetic field

Zhang Sheng Shi

We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependent rotating magnetic field.Based on the algebraic structure of the non-autonomouse system,the exact solution of the Schrdinger equation is obtained by using the method of algebraic dynamics.Based on the time-dependent analytical solution,we further study the entanglement evolution between the two coupled spins for different initial states,and find that the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.

Journal of Atomic and Molecular Physics•Jan 1, 2008•0 citations

Thermal entanglement in the system consisting of spin 1/2 and spin S

Mao-Fa Fang

Quantum thermal entanglement of two next nearest-neighbor qubits in a four-qubit isotropic Heisenberg XY model consisting of spin 1/2 and spin S in a homogeneous external magnetic field B was investigated by concurrence measure of entanglement.The results show that the external magnetic field can induce the thermal entanglement of two next nearest-neighbor qubits.The amplitude of thermal entanglement is dependent on the spin S,temperature T and homogeneous external magnetic field B.As a result,it is feasible to control thermal entanglement by adjusting the value of external magnetic field B.When S is sufficiently large,the threshold temperature above which there is no thermal entanglement may also be very high.The feature can be used in high-temperature entanglement of condensed matter systems and it will be useful in the research of quantum information in solid systems.

Chinese Journal of Quantum Electronics•Jan 1, 2008•0 citations

Entanglement in the XZ spin chain model in the external magnetic field

F. Soheilian, Mohammad Reza Soltani, M Firoozi +1 more

The entanglement at zero-temperature is studied in a two-qubit XZ spin-1/2 chain model in an external magnetic field which is applied in the z direction. We have obtained an analytical relation for the effect of the external magnetic field on the concurrence. It is shown that the ground state of the system depends on the strength of exchange coupling. We have shown that the analytical relation of the concurrence is independent of Jz. It is shown that for Jz >0 the concurrence is depended on the critical value of the external magnetic field and it is changed at the critical external magnetic field. Also we have shown that for h hc, the concurrence decreases by increasing the external magnetic field. For Jz <0, the concurrence decreases by increasing the external magnetic field.

Journal of Physical & Theoretical Chemistry•Dec 1, 2014•0 citations

Entanglement Evolution of Two-Coupled Spins in a Time-Dependent Rotating Magnetic Field

Zhang Shi-Xun, Qinsheng Zhu, Kuang Xiao-Yu

We study the dynamics evolution of a two-quhit Heisenherg XXX spin chain under a time-dependent rotating magnetic field. Based on the algebraic structure of the non-autonomous system, the exact solution of the Schrödinger equation is obtained by using the method of algebraic dynamics. Based on the time-dependent analytical solution, we further study the entanglement evolution between the two coupled spins for different initial states, and find that the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.

Communications in Theoretical Physics•Oct 1, 2008•1 citation

Based on algebraic dynamics and the concept of the concurrence of the entanglement,we investigate the evolutive properties of the TwoQubit entanglement that formed by Heisenberg XXX models under a time-dependent arbitrary external field.For this system,the property of the concurrence that is only dependent on the coupling constant J and total values of the external field is proved.Furthermore,we found that the thermal concurrence of the system under a static arbitrary external field is a function of the coupling constant J,temperature T and the magnitude of external field.

Based on algebraic dynamics and the concept of the concurrence of the entanglement, we investigate the evolutive properties of the two-qubit entanglement that formed by Heisenberg XXX models under a time-depending external held. For this system, the property of the concurrence that is only dependent on the coupling constant J and total values of the external field is proved. Furthermore, we found that the thermal concurrence of the system under a static random external field is a function of the coupling constant J , temperature T , and the magnitude of external held.

We study the entanglement of a two-qubit one-dimensional XYZ Heisenberg chain in thermal equilibrium at temperature T. We obtain an analytical expression for the concurrence of this system in terms of the parameters of the Hamiltonian and T. We show that depending on the relation among the coupling constants, it is possible to increase the amount of entanglement of the system by increasing its anisotropy. We also show numerically that for all sets of the coupling constants entanglement is a monotonically decreasing function of the temperature T, proving that we must have at least an external magnetic field in the z-direction to obtain a behavior where entanglement increases with T.

We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependent rotating magnetic field.Based on the algebraic structure of the non-autonomouse system,the exact solution of the Schrdinger equation is obtained by using the method of algebraic dynamics.Based on the time-dependent analytical solution,we further study the entanglement evolution between the two coupled spins for different initial states,and find that the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.

Quantum thermal entanglement of two next nearest-neighbor qubits in a four-qubit isotropic Heisenberg XY model consisting of spin 1/2 and spin S in a homogeneous external magnetic field B was investigated by concurrence measure of entanglement.The results show that the external magnetic field can induce the thermal entanglement of two next nearest-neighbor qubits.The amplitude of thermal entanglement is dependent on the spin S,temperature T and homogeneous external magnetic field B.As a result,it is feasible to control thermal entanglement by adjusting the value of external magnetic field B.When S is sufficiently large,the threshold temperature above which there is no thermal entanglement may also be very high.The feature can be used in high-temperature entanglement of condensed matter systems and it will be useful in the research of quantum information in solid systems.

The entanglement at zero-temperature is studied in a two-qubit XZ spin-1/2 chain model in an external magnetic field which is applied in the z direction. We have obtained an analytical relation for the effect of the external magnetic field on the concurrence. It is shown that the ground state of the system depends on the strength of exchange coupling. We have shown that the analytical relation of the concurrence is independent of Jz. It is shown that for Jz >0 the concurrence is depended on the critical value of the external magnetic field and it is changed at the critical external magnetic field. Also we have shown that for h hc, the concurrence decreases by increasing the external magnetic field. For Jz <0, the concurrence decreases by increasing the external magnetic field.

We study the dynamics evolution of a two-quhit Heisenherg XXX spin chain under a time-dependent rotating magnetic field. Based on the algebraic structure of the non-autonomous system, the exact solution of the Schrödinger equation is obtained by using the method of algebraic dynamics. Based on the time-dependent analytical solution, we further study the entanglement evolution between the two coupled spins for different initial states, and find that the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.