scholarly journals INFLUENCE OF ANISOTROPY AND MAGNETIC FIELD ON THERMAL ENTANGLEMENT IN HEISENBERG MODEL AND THERMODYNAMIC ANALYSIS OF MODEL

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Мilan Pantić ◽  
Nemanja Micić ◽  
Milica Pavkov Hrvojević ◽  
Slobodan Radošević ◽  
Petar Mali
Keyword(s):  
Magnetic Field ◽  
Thermodynamic Properties ◽  
Strong Magnetic Field ◽  
Thermodynamic Analysis ◽  
Interaction Parameter ◽  
Heisenberg Model ◽  
Thermal Entanglement ◽  
Dm Interaction ◽  
Analytical Expressions

The thermal entanglement in a two-qubit anisotropic Heisenberg XXZ system, also XYZ system, with Dzyaloshinskii-Moriya (DM) couplings in an inhomogenous magnetic field, was studied. The effects of these two kinds of anisotropies on the thermal entanglement have been studied in detail in the concept for concurrence, the measure of entanglement. The analytical expressions of concurrence are obtained for this model. It is found that the DM interaction can enhance thermal entanglement and can be efficiently controlled by the DM interaction parameter and ehchange interaction Jx, Jy and Jz. When D is large enough, the entanglement can exist for larger temperatures and strong magnetic field. We also analysed thermodynamic properties of Heisenberg model and the most important results were shown in the paper.

scholarly journals Thermal Entanglement and Critical Behavior of Magnetic Properties on a Triangulated Kagomé Lattice

10.14311/1344 ◽  
2011 ◽  
Vol 51 (2) ◽  
Author(s):  
N. Ananikian ◽  
L. Ananikyan ◽  
L. Chakhmakhchyan ◽  
A. Kocharian
Keyword(s):  
Magnetic Field ◽  
Heisenberg Model ◽  
Quantum Phase Transitions ◽  
Exchange Interactions ◽  
Effective Field ◽  
Threshold Temperature ◽  
Kagome Lattice ◽  
Thermal Entanglement ◽  
Kagomé Lattice ◽  
Bogoliubov Inequality

The equilibrium magnetic and entanglement properties in a spin-1/2 Ising-Heisenberg model on a triangulated Kagomé lattice are analyzed by means of the effective field for the Gibbs-Bogoliubov inequality. The calculation is reduced to decoupled individual (clusters) trimers due to the separable character of the Ising-type exchange interactions between the Heisenberg trimers. The concurrence in terms of the three qubit isotropic Heisenberg model in the effective Ising field in the absence of a magnetic field is non-zero. The magnetic and entanglement properties exhibit common (plateau, peak) features driven by a magnetic field and (antiferromagnetic) exchange interaction. The (quantum) entangled and non-entangled phases can be exploited as a useful tool for signalling the quantum phase transitions and crossovers at finite temperatures. The critical temperature of order-disorder coincides with the threshold temperature of thermal entanglement.

THERMAL ENTANGLEMENT IN SPIN-DIMER V4+ WITH A MAGNETIC FIELD

2003 ◽  
Vol 17 (10) ◽  
pp. 2129-2136
Author(s):  
GUO-FENG ZHANG ◽  
JIU-QING LIANG
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Critical Magnetic Field ◽  
Molecular Magnets ◽  
Thermal Entanglement ◽  
Anisotropic Parameter ◽  
Spin Dimer

By means of the measure of entanglement called "concurrence" we study the entanglement in Heisenberg dimer single molecular magnets V4+ with a strong magnetic field and find that thermal entanglement exits for both ferromagnetic (FM) and antiferromagnetic (AFM) cases. In FM case entanglement vanishes for anisotropic parameter λ = 0 while in AFM case, entanglement exits in the whole region of anisotropic parameter 0 ≤ λ ≤ 1. Entanglement variations with anisotropic parameter λ, magnetic field B and temperature T are evaluated. We find a critical magnetic field at which the concurrence changes sharply from zero to maximum entanglement.

ENTANGLEMENT IN THE XY HEISENBERG MODEL

2004 ◽  
Vol 18 (19n20) ◽  
pp. 1059-1065 ◽  
Author(s):  
XIN TIAN ◽  
JIA-TIH LIN ◽  
LIANG LIU ◽  
DE-LONG REN
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Ising Model ◽  
Heisenberg Model ◽  
Nonuniform Magnetic Field ◽  
Xy Model ◽  
Thermal Entanglement ◽  
Isotropic Model

We investigate the thermal entanglement of two-qubit anisotropic Heisenberg XY model in the presence of an external nonuniform magnetic field B along the z-axis. Concurrence, the measure of entanglement is calculated and its property is studied in different cases. Two best models, Ising model under a uniform magnetic and isotropic model in a nonuniform magnetic field, are discovered. In the two models, the critical temperature Tc (above which there is no entanglement) can be enhanced and its concurrence is maximal.

PAIRWISE ENTANGLEMENT IN THE N-QUBIT XX MODEL WITH DZYALOSHINSKI–MORIYA INTERACTION AND MAGNETIC FIELD

2011 ◽  
Vol 25 (16) ◽  
pp. 2135-2148
Author(s):  
BIN ZHOU
Keyword(s):  
Magnetic Field ◽  
Critical Temperature ◽  
Magnetic Fields ◽  
Nearest Neighbor ◽  
Zero Temperature ◽  
Thermal Entanglement ◽  
Dm Interaction ◽  
Xx Model ◽  
Moriya Interaction

In this paper, we investigate the role of Dzyaloshinski–Moriya (DM) interaction in the pairwise entanglement in the three- and four-qubit XX models with magnetic field. In the four-qubit model, the pairwise entanglements of two nearest-neighbor qubits and two next-neighbor qubits are investigated, respectively. The dependences of the critical temperature at which the pairwise thermal entanglement disappears on DM interaction and magnetic fields are studied in details. At zero temperature, the entanglement can undergo sudden changes with adjustment of the parameters, and the general results of the concurrence are obtained in all cases.

Thermal entanglement in a mixed spin Heisenberg XXX chain with DM interaction

2021 ◽  
pp. 2150021
Author(s):  
Nizar Ahami ◽  
Morad El Baz
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Thermal Entanglement ◽  
Bipartite Entanglement ◽  
Dm Interaction ◽  
One Dimensional ◽  
Mixed Spin ◽  
Xxx Model ◽  
Moriya Interaction ◽  
Heisenberg Xxx Model

We consider a one-dimensional, mixed spin Heisenberg XXX model with an homogeneous external magnetic field and Dzyaloshinskii–Moriya interaction. Alternating spin-[Formula: see text] and spin-1 particles are forming the chain. The effect of the different parameters of the system on the bipartite thermal entanglement is studied. The type of chain used (mixed) and the size of the chain ([Formula: see text]) allow to study three types of bipartite entanglement, the qubit–qubit, qubit–qutrit and qutrit–qutrit thermal entanglement.

THREE-QUBITS GROUND STATE AND THERMAL ENTANGLEMENT OF ANISOTROPIC HEISENBERG (XXZ) AND ISING MODELS WITH DZYALOSHINSKII-MORIYA INTERACTION

2011 ◽  
Vol 09 (04) ◽  
pp. 1057-1079 ◽  
Author(s):  
R. JAFARI ◽  
A. LANGARI
Keyword(s):  
Magnetic Field ◽  
Ground State ◽  
Ising Models ◽  
Zero Temperature ◽  
Thermal Entanglement ◽  
Xxz Model ◽  
Dm Interaction ◽  
Remarkable Result ◽  
Moriya Interaction ◽  
Heisenberg Xxz Model

We have studied the symmetric and non-symmetric pairwise ground state and thermal entanglement in three-qubits system. We have considered the anisotropic Heisenberg (XXZ) model in the presence of Dzyaloshinskii–Moriya (DM) interaction in addition to the Ising model in a magnetic field with DM interaction. We have found that the increment of DM interaction and magnetic field can enhance and reduce the entanglement of the system. We have shown that the non-symmetric pairwise state has higher value concurrence and critical temperature (above which the entanglement vanishes) than the symmetric pairwise one. For the negative anisotropy, the non-symmetric entanglement is a monotonic function of DM interaction while for positive anisotropy, it has a maximum versus DM parameter and vanishes for larger values of DM interaction. The conditions for the existence of thermal entanglement are discussed in detail. The most remarkable result appears at zero temperature where the three-qubits ground state entanglement of the system (in spite of two-qubits counterpart) shows the fingerprint of the quantum phase transition for a system of infinite number of qubits.

MAGNETIZATION PLATEAUS ON THE ZIGZAG LADDER WITH TWO-, AND THREE-SITE EXCHANGES

2007 ◽  
Vol 21 (20) ◽  
pp. 3567-3579 ◽  
Author(s):  
V. V. HOVHANNISYAN ◽  
L. N. ANANIKYAN ◽  
N. S. ANANIKIAN
Keyword(s):  
Magnetic Field ◽  
Partition Function ◽  
Strong Magnetic Field ◽  
Low Temperatures ◽  
Heisenberg Model ◽  
Spin Exchange ◽  
Exchange Interactions ◽  
Exact Results ◽  
Recursion Method ◽  
Exchange Parameters

We consider the Heisenberg model with two-, and three-spin exchange interactions on a zigzag ladder in a strong magnetic field. Using the recursion method for the partition function in Ising approximation we have found exact results for the magnetization. We have shown the existence of magnetization plateaus in the case of mutual two-, and three-spin exchanges at low temperatures and different exchange parameters. The system exhibits different magnetic behaviors, depending on the values of the exchange parameters.

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