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.

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.

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.

Unveiling the thermal entanglement in a mixed-spin XXZ model with Dzyaloshinskii–Moriya interaction under a homogeneous magnetic field

2015 ◽  
Vol 29 (03) ◽  
pp. 1550005 ◽  
Author(s):  
Cheng-Cheng Liu ◽  
Shuai Xu ◽  
Juan He ◽  
Liu Ye
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Homogeneous Magnetic Field ◽  
Coupling Constant ◽  
Thermal Entanglement ◽  
Xxz Model ◽  
Dm Interaction ◽  
Mixed Spin ◽  
External Magnetic Field Strength ◽  
Moriya Interaction

We analytically investigate the thermal entanglement of three-mixed-spin (1/2, 1, 1/2) XXZ model with the DM interaction under an external magnetic field B. Two different cases are considered: one subsystem (1/2, 1/2) consists of two spin-1/2 fermions and the other subsystem (1/2, 1) contains a spin-1/2 fermion and a spin-1 boson. It is shown that the DM interaction parameter D, the external magnetic field strength B and coupling constant J have different effects on Fermi and mixed Fermi–Bose systems. All of the factors mentioned above can be utilized to control entanglement switch of any two particles in mixed spins model.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

scholarly journals Temperature-Induced Plasmon Excitations for the α–T3 Lattice in Perpendicular Magnetic Field

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1720
Author(s):  
Antonios Balassis ◽  
Godfrey Gumbs ◽  
Oleksiy Roslyak
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Zeeman Splitting ◽  
Mass Term ◽  
Energy Dispersive Spectrum ◽  
Wave Functions ◽  
Transition Energies ◽  
Gap Opening ◽  
Quantizing Magnetic Field

We have investigated the α–T3 model in the presence of a mass term which opens a gap in the energy dispersive spectrum, as well as under a uniform perpendicular quantizing magnetic field. The gap opening mass term plays the role of Zeeman splitting at low magnetic fields for this pseudospin-1 system, and, as a consequence, we are able to compare physical properties of the the α–T3 model at low and high magnetic fields. Specifically, we explore the magnetoplasmon dispersion relation in these two extreme limits. Central to the calculation of these collective modes is the dielectric function which is determined by the polarizability of the system. This latter function is generated by transition energies between subband states, as well as the overlap of their wave functions.

scholarly journals EFFECT OF DIFFERENT DZYALOSHINSKII–MORIYA INTERACTIONS ON ENTANGLEMENT IN THE HEISENBERG XYZ CHAIN

2009 ◽  
Vol 07 (02) ◽  
pp. 547-557 ◽  
Author(s):  
DA-CHUANG LI ◽  
ZHUO-LIANG CAO
Keyword(s):  
Critical Temperature ◽  
Coupling Coefficient ◽  
Control Parameter ◽  
Spin Coupling ◽  
Thermal Entanglement ◽  
Coupling Interaction ◽  
Dm Interaction ◽  
Coupling Parameters

In this paper, we study the thermal entanglement in a two-qubit Heisenberg XYZ system with different Dzyaloshinskii–Moriya (DM) couplings. We show that different DM coupling parameters have different influences on the entanglement and the critical temperature. In addition, we find that when Ji (i-component spin coupling interaction) is the largest spin coupling coefficient, Di (i-component DM interaction) is the most efficient DM control parameter, which can be obtained by adjusting the direction of DM interaction.

Schwinger effect in an instanton background with electric and magnetic fields via holography

2018 ◽  
Vol 33 (25) ◽  
pp. 1850144
Author(s):  
Maryam Gholizadeh Arashti ◽  
Majid Dehghani
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Production Rate ◽  
Pair Creation ◽  
Zero Temperature ◽  
Expectation Value ◽  
Background Magnetic Field ◽  
Electric And Magnetic Fields ◽  
Schwinger Effect ◽  
Horizon Limit

The Schwinger effect in the presence of instantons and background magnetic field was considered to study the dependence of critical electric field on instanton density and magnetic field using AdS/CFT conjecture. The gravity side is the near horizon limit of D3[Formula: see text]D(−[Formula: see text]1) background with electric and magnetic fields on the brane. Our approach is based on the potential analysis for particle–antiparticle pair at zero and finite temperatures, where the zero temperature case is a semi-confining theory. We find that presence of instantons suppresses the pair creation effect, similar to a background magnetic field. Then, the production rate will be obtained numerically using the expectation value of circular Wilson loop. The obtained production rate in a magnetic field is in agreement with previous results.

THERMAL ENTANGLEMENT OF A TWO-QUTRIT XXZ SPIN CHAIN WITH DZIALOSHISKI-MORIYA INTERACTION

2009 ◽  
Vol 07 (05) ◽  
pp. 1021-1028
Author(s):  
XIAO SAN MA
Keyword(s):  
Spin Chain ◽  
Thermal Entanglement ◽  
Strong Anisotropy ◽  
Weak Anisotropy ◽  
Positive Role ◽  
Dm Interaction ◽  
Entanglement Evolution ◽  
Maximum Value ◽  
Moriya Interaction

The effect of Dzialoshiski-Moriya (DM) interaction and anisotropy on the thermal entanglement of a two-qutrit XXZ spin chain is investigated. Our analysis implies that the DM interaction and weak anisotropy can enhance the thermal entanglement to a maximum value while the strong anisotropy plays a positive role in shrinking thermal entanglement. Furthermore, we find that the entanglement evolution in terms of anisotropy is sensitive to weak anisotropy.

scholarly journals Doppler Images of Rapidly Rotating Ap Stars

1988 ◽  
Vol 132 ◽  
pp. 199-204
Author(s):  
Artie P. Hatzes
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Stellar Surface ◽  
Surface Distribution ◽  
Distribution Of Elements ◽  
Local Equivalent ◽  
Field Geometry ◽  
A New Technique ◽  
Ap Stars

The magnetic Ap stars are characterized by the presence of large magnetic fields which undergo periodic variations. These magnetic field variations are accompanied by spectral variations caused by the inhomogeneous distribution of elements on the stellar surface. It is believed that the magnetic field plays an important role in determining this distribution. Accurate maps of the surface distribution of elements would provide valuable probes as to the field geometry as well as provide clues to the role of the magnetic fields in the atmospheres of these stars. We have developed a new technique for mapping the local equivalent width on a stellar surface from the observed spectral line variations.

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