Phase diagram of the antiferromagnetic XY model with a triangular lattice in an external magnetic field

1986 ◽  
Vol 19 (29) ◽  
pp. 5927-5935 ◽  
Author(s):  
S E Korshunov
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
External Magnetic Field ◽  
Triangular Lattice ◽  
Xy Model

Chiral condensate of cold dense quark matter with external magnetic field

2020 ◽  
Vol 35 (19) ◽  
pp. 2050160
Author(s):  
Song Shi ◽  
Juan Liu
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
External Magnetic Field ◽  
Quark Matter ◽  
Chemical Potential ◽  
Field Approximation ◽  
Chiral Condensate ◽  
Mean Field Approximation ◽  
Dynamical Mass ◽  
Dense Quark Matter

At zero temperature and finite chemical potential, the gap equation of cold dense quark matter under external magnetic field is studied with NJL model in the mean-field approximation. By introducing new methods, it is found that the Nambu phase has sophisticated structures which have not been studied before. As a consequence, the phase diagram is expanded and divided into five areas, in each area the condensate has unique behaviors with chemical potential varying. Furthermore, the expanded phase diagram is used to predict the order of phase transition between the Nambu phase and the Wigner phase, it can also be used to explain the relations of dynamical mass and chemical potential. Meanwhile, the metastable states and cascade effect of dynamical mass are studied in this paper.

Time evolution of quantum-memory-assisted entropic uncertainty relation and quantum correlations under dissipative environment

2019 ◽  
Vol 17 (01) ◽  
pp. 1950008 ◽  
Author(s):  
Mohammad Reza Pourkarimi
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Time Evolution ◽  
Uncertainty Relation ◽  
Quantum Correlations ◽  
Quantum Memory ◽  
Xy Model ◽  
Anisotropic Parameter ◽  
Entropic Uncertainty Relation ◽  
Dissipative Environment

By assuming the effect of dissipative environment and the Hamiltonian XY-model and external magnetic field, the time evolution of the entropic uncertainty relation (EUR) in the presence of quantum-memory and the dynamics of quantum correlations (QC) are investigated. It is shown that EUR and QC may evolve in different ways during the time. However, they can behave similarly when the time tends to infinity. The effects of external magnetic field and anisotropic parameter are different on the dynamics of EUR and QC.

STABILITY OF SKYRMIONS IN THE FRUSTRATED ANTIFERROMAGNETIC/FERROELECTRIC BILAYERS WITH THE TRIANGULAR LATTICE

2021 ◽  
Vol 0 (1) ◽  
pp. 17-22
Author(s):  
I.F. SHARAFULLIN ◽  
◽  
A.R. YULDASHEVA ◽  
N.M. NUGAEVA ◽  
H.T. DIEP ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Triangular Lattice ◽  
Ground State ◽  
Steepest Descent Method ◽  
Magnetic Phase Transitions ◽  
Magnetoelectric Interaction ◽  
Spin Configuration ◽  
Ferroelectric Layer ◽  
Antiferromagnetic Layer

The formation and conditions of stability of a skyrmions at the interface between a ferroelectric layer and antiferromagnetic layer with triangilar lattice and its phase transition are studied. All interactions between spins and polarizations are limited to nearest neighbors (NN). The antiferromagnetic exchange interaction among the spins inside antiferromagnetic layer will compete with the perpendicular interface interaction between adjacent layers. The ground state spin configuration at zero temperature is calculated by using the numerical high performance steepest descent method. The resulting configuration is non-collinear. Small values of external field yields small values of angles between spins in the plane so that the ground state configurations have antiferromagnetic and non collinear domains. We observe the creation of single spin vortices. We noted that for zero applied magnetic field the skyrmions in the antiferromagnetic/ferroelectric bilayers with triangular lattice can be created in the region of interface magnetoelectric interaction value between 0.85 and 1.95. The strong external magnetic field applied perpendicular to the interface with non-collinear Dzyaloshinskiy-Morya-like magnetoelectric interaction at the interface leads to remove the skyrmion phase and magnetic phase transitions. With increasing the interface magnetoelectric coupling, the skyrmion lattice disappear. We found the formation perfect skyrmion structure at non-zero external magnetic field and moderate values of magnetoelectric interaction. The skyrmions structure is stable in a large region of the interface magnetoelectric interaction between antiferromagnetic and ferroelectric films. The results of Monte Carlo simulations that we carried out confirm that observed skyrmions are stable up to a finite temperature.

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