Entanglement in the Mixed-three-spin $XXX$ Heisenberg Model with the Next-nearest-neighbour InteractionEntanglement in the Mixed-three-spin $XXX$ Heisenberg Model with the Next-nearest-neighbour Interaction

Hamid Arian Zad

In this paper, we investigate thermal pairwise quantum correlation for any pair of spins of a mixed-three-spin XXX Heisenberg system (with spins connected together with the nearest-neighbour (NN) and that of the next-nearest-neighbour (NNN) coupling constants J 1 and J 2 ) by means of concurrence and quantum discord, as functions of temperature T , magnetic field B and the coupling constants J 2 and J 1 .Some comparisons between these measures of entanglement are done for next-nearest-neighbour spins.We also express some magnetic properties and discuss the behaviour of the system in some special critical points.Some interesting and novel discussions are done to introduce some entanglement witnesses.In this paper, we investigate thermal pairwise quantum correlation for any pair of spins of a mixed-three-spin XXX Heisenberg system (with spins connected together with the nearest-neighbour (NN) and that of the next-nearest-neighbour (NNN) coupling constants J 1 and J 2 ) by means of concurrence and quantum discord, as functions of temperature T , magnetic field B and the coupling constants J 2 and J 1 .Some comparisons between these measures of entanglement are done for next-nearest-neighbour spins.We also express some magnetic properties and discuss the behaviour of the system in some special critical points.Some interesting and novel discussions are done to introduce some entanglement witnesses.

Acta Physica Polonica BJan 1, 20158 citations

Forward--Backward Multiplicity Correlations in Relativistic Heavy-ion Collisions

Waseem Bari, Qudsia Gani, Shamsul H. Thoker +1 more

Acta Physica Polonica BJan 1, 20153 citations

Effects of a Pulsatile Flow and an Endoscope on the Peristaltic Transport of a Newtonian Fluid

H. Rachid, M. T. Ouazzani, Mehdi Riahi

Acta Physica Polonica BJan 1, 20153 citations

Magnetic quantum correlations in the one-dimensional transverse-field XXZ model

Salimeh Mahdavifar, S. Mahdavifar, Rouhollah Jafari

One-dimensional spin- $\frac{1}{2}$ systems are well-known candidates to study the quantum correlations between particles. In condensed matter physics, studies often are restricted to first-neighbor particles. In this work, we consider the one-dimensional $XXZ$ model in a transverse magnetic field (TF) which is not integrable except at specific points. Analytical expressions for quantum correlations (entanglement and quantum discord) between spin pairs at any distance are obtained for both zero and finite temperature by using the analytical approach proposed by Caux et al. [Phys. Rev. B 68, 134431 (2003)]. We compare the efficiency of the quantum discord (QD) with respect to the entanglement in the detection of critical points as the neighboring spin pairs go farther than the next-nearest neighbors. In the absence of the TF and at zero temperature, we show that the QD for spin pairs farther than the second neighbors is able to capture the critical points while the pairwise entanglement is absent. In contrast with the pairwise entanglement, two-site QD is effectively long range in the critical regimes where it decays algebraically with the distance between pairs. We also show that the thermal QD between neighbor spins possesses strong distinctive behavior at the critical point that can be seen at finite temperature and, therefore, spotlights the critical point while the entanglement fails in this task.One-dimensional spin-$\frac{1}{2}$ systems are well-known candidates to study the quantum correlations between particles. In condensed matter physics, studies often are restricted to first-neighbor particles. In this work, we consider the one-dimensional $XXZ$ model in a transverse magnetic field (TF) which is not integrable except at specific points. Analytical expressions for quantum correlations (entanglement and quantum discord) between spin pairs at any distance are obtained for both zero and finite temperature by using the analytical approach proposed by Caux et al. [Phys. Rev. B 68, 134431 (2003)]. We compare the efficiency of the quantum discord (QD) with respect to the entanglement in the detection of critical points as the neighboring spin pairs go farther than the next-nearest neighbors. In the absence of the TF and at zero temperature, we show that the QD for spin pairs farther than the second neighbors is able to capture the critical points while the pairwise entanglement is absent. In contrast with the pairwise entanglement, two-site QD is effectively long range in the critical regimes where it decays algebraically with the distance between pairs. We also show that the thermal QD between neighbor spins possesses strong distinctive behavior at the critical point that can be seen at finite temperature and, therefore, spotlights the critical point while the entanglement fails in this task.

arXiv:1710.05390Physical Review ANov 2, 201736 citations

Efiects of the Next-Nearest-Neighbor Interaction on the Entanglement of the Heisenberg XX Chain *

Ming‐Liang Hu, Tian Dong-Ping

Abstract The pairwise entanglement of the Heisenberg XX chain with next-nearest-neighbor (NNN) interac-tions was investigated by using the concurrence measure. The results show that for the nearest-neighbor sites,the entanglement may be improved or suppressed depending on the magnitudes of the NNN coupling constant J , while for the next-nearest-neighbor sites, it always increases with the increase of jJj . The critical tempera-ture T c decreases with the increase of J for the nearest-neighbor entanglement and increases with the increaseof jJj for the next-nearest-neighbor entanglement, respectively. We also show that the general Heisenberg XXmodel still can be used to create the entangled W states of three and four qubits, and that the presence ofNNN coupling has no eﬁect on the creation of four-qubit W states, while it shifts the instant of time at whichthe three-qubit W states are created.Key words Heisenberg XX chain, next-nearest-neighbor interaction, thermal entanglement 1 IntroductionAbstract The pairwise entanglement of the Heisenberg XX chain with next-nearest-neighbor (NNN) interac-tions was investigated by using the concurrence measure. The results show that for the nearest-neighbor sites,the entanglement may be improved or suppressed depending on the magnitudes of the NNN coupling constant J , while for the next-nearest-neighbor sites, it always increases with the increase of jJj . The critical tempera-ture T c decreases with the increase of J for the nearest-neighbor entanglement and increases with the increaseof jJj for the next-nearest-neighbor entanglement, respectively. We also show that the general Heisenberg XXmodel still can be used to create the entangled W states of three and four qubits, and that the presence ofNNN coupling has no eﬁect on the creation of four-qubit W states, while it shifts the instant of time at whichthe three-qubit W states are created.Key words Heisenberg XX chain, next-nearest-neighbor interaction, thermal entanglement 1 Introduction

Jan 1, 20060 citations

Quantum correlations in a cluster spin model with three-spin interactions

F Sadaf, V. Subrahmanyam

Abstract An exactly solvable cluster spin model with three-spin interaction couplings Jx(for XZX spin components) and J y (for YZY spin components) in the presence of a transverse magnetic field h for a spin chain is investigated. For h = 0, and with only one non-zero interaction strength, the ground state is the cluster state. Through the Jordan–Wigner fermion mapping, the odd sites and the even sites form two separate transverse-XY chains, connected only through the boundary terms. Consequently, all measures of quantum correlations for nearest neighbour spins, the concurrence, the quantum mutual information and the quantum discord are all zero in the ground state. The dynamics is spin conserving for J y = J x , exhibiting a line of critical points for | h / J x | ⩽ 2 , with an uncorrelated direct product ground state for | h / J x | > 2 . There are several quantum critical points in the parameter space, with multi-fold degenerate ground states. The magnetisation and the global entanglement measure exhibit strong singular features for the spin conserving case. The next-neighbour quantum correlation measures are investigated analytically, which exhibit singular features in the vicinity of degeneracy critical points. The Jy - and h- derivatives of the concurrence exhibit singular peak behaviour near the degeneracy critical points, except in the spin conserving case where the derivatives are zero.Abstract An exactly solvable cluster spin model with three-spin interaction couplings Jx(for XZX spin components) and J y (for YZY spin components) in the presence of a transverse magnetic field h for a spin chain is investigated. For h = 0, and with only one non-zero interaction strength, the ground state is the cluster state. Through the Jordan–Wigner fermion mapping, the odd sites and the even sites form two separate transverse-XY chains, connected only through the boundary terms. Consequently, all measures of quantum correlations for nearest neighbour spins, the concurrence, the quantum mutual information and the quantum discord are all zero in the ground state. The dynamics is spin conserving for J y = J x , exhibiting a line of critical points for | h / J x | ⩽ 2 , with an uncorrelated direct product ground state for | h / J x | > 2 . There are several quantum critical points in the parameter space, with multi-fold degenerate ground states. The magnetisation and the global entanglement measure exhibit strong singular features for the spin conserving case. The next-neighbour quantum correlation measures are investigated analytically, which exhibit singular features in the vicinity of degeneracy critical points. The Jy - and h- derivatives of the concurrence exhibit singular peak behaviour near the degeneracy critical points, except in the spin conserving case where the derivatives are zero.

arXiv:2503.14060Journal of Physics A Mathematical and TheoreticalMar 18, 20251 citation

Entanglement in the Mixed-three-spin

XXX

Heisenberg Model with the Next-nearest-neighbour Interaction

One-dimensional spin-

\frac{1}{2}

systems are well-known candidates to study the quantum correlations between particles. In condensed matter physics, studies often are restricted to first-neighbor particles. In this work, we consider the one-dimensional

XXZ

model in a transverse magnetic field (TF) which is not integrable except at specific points. Analytical expressions for quantum correlations (entanglement and quantum discord) between spin pairs at any distance are obtained for both zero and finite temperature by using the analytical approach proposed by Caux et al. [Phys. Rev. B 68, 134431 (2003)]. We compare the efficiency of the quantum discord (QD) with respect to the entanglement in the detection of critical points as the neighboring spin pairs go farther than the next-nearest neighbors. In the absence of the TF and at zero temperature, we show that the QD for spin pairs farther than the second neighbors is able to capture the critical points while the pairwise entanglement is absent. In contrast with the pairwise entanglement, two-site QD is effectively long range in the critical regimes where it decays algebraically with the distance between pairs. We also show that the thermal QD between neighbor spins possesses strong distinctive behavior at the critical point that can be seen at finite temperature and, therefore, spotlights the critical point while the entanglement fails in this task.