scholarly journals CORRELATION FUNCTIONS OF MULTISITE INTERACTION SPIN-S MODELS ON THE BETHE-LIKE LATTICES

2000 ◽  
Vol 14 (06) ◽  
pp. 589-602
Author(s):  
R. G. GHULGHAZARYAN
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Magnetic Susceptibility ◽  
External Magnetic Field ◽  
Correlation Length ◽  
Correlation Functions ◽  
Critical Index ◽  
Spin Correlation ◽  
Phase Transition Region ◽  
Second Order Phase Transition

Multisite interaction spin-S models in an external magnetic field are studied recursively on the Bethe-like lattices. The transfer-matrix method is extended to calculate exactly the two-spin correlation functions. The exact expressions for the correlation length and magnetic susceptibility are derived for spin-1/2 models. The singularity of the correlation length with critical index ν = 1 and the proportionality of magnetic susceptibility to correlation length in the second order phase transition region of spin-1/2 ferromagnetic models on the Bethe-like lattices are established analytically.

scholarly journals Влияние магнитного поля на термодинамические и магнитные свойства антиферромагнитной модели Изинга на объемно-центрированной кубической решетке

2020 ◽  
Vol 62 (2) ◽  
pp. 229
Author(s):  
А.К. Муртазаев ◽  
М.К. Рамазанов ◽  
К.Ш. Муртазаев ◽  
М.А. Магомедов ◽  
М.К. Бадиев
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Three Dimensional ◽  
Nearest Neighbors ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
The Monte Carlo Method ◽  
Body Centered Cubic Lattice ◽  
Second Order Phase Transition

The influence of the external magnetic field on the phase transitions, thermodynamic and magnetic properties of the three-dimensional Ising model of antiferromagnetic on a body-centered cubic lattice taking into account the interactions of the second nearest neighbors is studied by the replica algorithm of the Monte Carlo method. A phase diagram of the dependence of the critical temperature on the external magnetic field has been constructed. It is shown that a second-order phase transition is observed in the considered range of magnetic field values

Untersuchungen zur Quantenkondensation

1974 ◽  
Vol 29 (10) ◽  
pp. 1387-1393
Author(s):  
P. L. Lin
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Thermodynamic Limit ◽  
Order Phase Transition ◽  
Rotating System ◽  
One Dimensional ◽  
Charged System ◽  
Three Space ◽  
Second Order Phase Transition

Abstract It has recently been proved that quantum condensation can possibly occur only when the thermodynamic limit is formed with respect to all three space dimensions. Following this idea, it is shown that a rotating system is practically one-dimensional and therefore does not permit quantum condensation. The same is true for a charged system in an external magnetic field. However, an exact proof is given only for a second order phase transition.

INFLUENCE OF AN EXTERNAL MAGNETIC FIELD ON THE DYNAMICS OF A NEW-PHASE NUCLEUS IN THE VICINITY OF THE FIRST-ORDER PHASE TRANSITION IN MAGNETS WITH DEFECTS PRESENT

2012 ◽  
Vol 26 (28) ◽  
pp. 1250183 ◽  
Author(s):  
VLADIMIR NAZAROV ◽  
RISHAT SHAFEEV
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
External Magnetic Field ◽  
Magnetic Anisotropy ◽  
Spin Reorientation ◽  
Critical Fields ◽  
First Order ◽  
Phase Nucleus ◽  
First Order Phase Transition ◽  
New Phase

Theoretically, with the aid of a soliton model, the evolution of a new-phase nucleus near the first-order spin-reorientation phase transition in magnets has been investigated in an external magnetic field. The influence of an external field and one-dimensional defects of magnetic anisotropy on the dynamics of such nucleus has been demonstrated. The conditions for the localization of the new-phase nucleus in the region of the magnetic anisotropy defect and for its escape from the defect have been determined. The values of the critical fields which bring about the sample magnetization reversal have been identified and estimated.

A NONPERTURBATIVE CALCULATION FOR THE EFFECTIVE POTENTIAL OF THE $\left(\frac{g}{4}\phi^{4}-J\phi\right)_{1+1}$ SCALAR FIELD THEORY USING THE OSCILLATOR REPRESENTATION METHOD WITH BOREL RESUMMATION

2007 ◽  
Vol 22 (06) ◽  
pp. 1265-1278
Author(s):  
ABOUZEID M. SHALABY ◽  
S. T. EL-BASYOUNY
Keyword(s):  
Magnetic Field ◽  
Field Theory ◽  
Phase Transition ◽  
Scalar Field ◽  
External Magnetic Field ◽  
Effective Potential ◽  
Oscillator Representation ◽  
Constructive Field Theory ◽  
Representation Method ◽  
Oscillator Representation Method

We established a resummed formula for the effective potential of [Formula: see text] scalar field theory that can mimic the true effective potential not only at the critical region but also at any point in the coupling space. We first extend the effective potential from the oscillator representation method, perturbatively, up to g3 order. We supplement perturbations by the use of a resummation algorithm, originally due to Kleinert, Thoms and Janke, which has the privilege of using the strong coupling as well as the large coupling behaviors rather than the conventional resummation techniques which use only the large order behavior. Accordingly, although the perturbation series available is up to g3 order, we found a good agreement between our resummed effective potential and the well-known features from constructive field theory. The resummed effective potential agrees well with the constructive field theory results concerning existing and order of phase transition in the absence of an external magnetic field. In the presence of the external magnetic field, as in magnetic systems, the effective potential shows nonexistence of phase transition and gives the behavior of the vacuum condensate as a monotonic increasing function of J, in complete agreement with constructive field theory methods.

Monte Carlo Modelling of Phase Transitions in Quasi-One-Dimensional Multiferoic

2016 ◽  
Vol 845 ◽  
pp. 158-161
Author(s):  
S.J. Lamekhov ◽  
Dmitry A. Kuzmin ◽  
Igor V. Bychkov ◽  
I.A. Maltsev ◽  
V.G. Shavrov
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Monte Carlo Method ◽  
External Magnetic Field ◽  
Periodic Potential ◽  
One Dimensional ◽  
Field Modelling ◽  
Energy Components

Behavior of quasi-one-dimensional multiferoic Ca3CoMnO6 in external magnetic field was investigated. Modelling by Monte Carlo method was performed to show influence of external magnetic field on appearance of polarization and temperature of phase transition in electric subsystem. Magnetization, polarization and energy components for magnetic and electric subsystems dependencies were achieved for different values of external magnetic field. Modelling showed that periodic potential in form of Frenkel-Kontorova makes influence on maximal values and temperature of phase transitions for magnetization and polarization.

LANDAU LEVELS AND VERTEX OPERATIONS FOR ANYONS

1991 ◽  
Vol 06 (30) ◽  
pp. 2819-2826 ◽  
Author(s):  
GERALD V. DUNNE ◽  
ALBERTO LERDA ◽  
CARLO A. TRUGENBERGER
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
External Magnetic Field ◽  
String Theory ◽  
Ground State ◽  
Correlation Functions ◽  
Landau Levels ◽  
Vertex Operators ◽  
Many Body

We construct exact many-body eigenstates of both energy and angular momentum for the N-anyon problem in an external magnetic field. We show that such states span the full ground state eigenspace and arise as correlation functions of Fubini-Veneziano vertex operators of string theory.

A variational calculation of magnetized correlated fermion system using a spin-dependent correlation: Application to liquid 3He

2015 ◽  
Vol 29 (07) ◽  
pp. 1550046 ◽  
Author(s):  
Gholam Hossein Bordbar ◽  
Mohammad Taghi Mohammadi Sabet
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Correlation Function ◽  
Magnetic Fields ◽  
Spin Correlation ◽  
Variational Calculation ◽  
Fermion System ◽  
Magnetic Instability ◽  
Spin Correlation Function ◽  
Dependent Correlation

In the presence of magnetic field, we have employed a spin-dependent correlation function to investigate the properties of liquid 3 He using the variational method based on the cluster expansion of the energy. It has been indicated that at all relevant magnetic fields and densities, the inclusion of spin-dependency for the correlation function leads to the lower magnitudes for the kinetic, magnetic and potential energies, and therefore the total energy of this system. We have seen that the spin–spin correlation affects the system to be less magnetized compared to the case in which we consider the spin-independent correlation, especially at low densities. In the case of spin–spin correlation function, our results show a maximum in the magnetic susceptibility, and therefore a meta-magnetic instability for the system for the magnetic fields in the range 50 T ≤ B ≤ 60 T . This behavior has not been observed in the case of spin-independent correlation.

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