Phase structure of a Yukawa-like model in the presence of magnetic background and boundaries

2016 ◽  
Vol 31 (23) ◽  
pp. 1650128 ◽  
Author(s):  
L. M. Abreu ◽  
E. S. Nery
Keyword(s):  
Magnetic Field ◽  
Phase Structure ◽  
Vector Fields ◽  
Strong Dependence ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Complex Scalar ◽  
Scalar And Vector Fields ◽  
Complex Scalar Field

In this paper, we investigate the thermodynamics of a Yukawa-like model, constituted of a complex scalar field interacting with real scalar and vector fields, in the presence of an external magnetic field and boundaries. By making use of mean-field approximation, we analyze the phase structure of this model at effective chemical equilibrium, under change of values of the relevant parameters of the model, focusing on the influence of the boundaries on the phase structure. The findings reveal a strong dependence of the nature of the phase structure on temperature, magnetic background and size of compactified coordinate, with possibility of a two-step phase transition.

Phase structure of the scalar Yukawa model with compactified spatial dimensions

2016 ◽  
Vol 31 (20) ◽  
pp. 1650121 ◽  
Author(s):  
L. M. Abreu ◽  
A. P. C. Malbouisson ◽  
E. S. Nery
Keyword(s):  
Field Theory ◽  
Phase Structure ◽  
Vector Fields ◽  
Boundary Effects ◽  
Quantum Field ◽  
Yukawa Model ◽  
Complex Scalar ◽  
Scalar And Vector Fields ◽  
Spatial Dimensions ◽  
Complex Scalar Field

In this work, we investigate the thermodynamic behavior of the generalized scalar Yukawa model, composed of a complex scalar field interacting with real scalar and vector fields. In particular, boundary effects on the phase structure are discussed using methods of quantum field theory on toroidal topologies. We concentrate on the dependence of the thermodynamics with the number of compactified spatial dimensions. In this sense, the phase transitions are analyzed and compared with the system in the situations of one, two and three compactified spatial dimensions. Our findings suggest that the presence of more boundaries tends to inhibit the broken phase.

scholarly journals The Combined Effect of Rotation and Magnetic Field on Finite-Amplitude Thermal Convection

1973 ◽  
Vol 26 (5) ◽  
pp. 617 ◽  
Author(s):  
R Van der Borght ◽  
JO Murphy
Keyword(s):  
Magnetic Field ◽  
Mean Field ◽  
Field Approximation ◽  
Finite Amplitude ◽  
Combined Effect ◽  
Mean Field Approximation ◽  
Free Boundaries ◽  
Wide Range ◽  
The Mean ◽  
Basic Equations

The combined effect of an imposed rotation and magnetic field on convective transfer in a horizontal Boussinesq layer of fluid heated from below is studied in the mean field approximation. The basic equations are derived by a variational technique and their solutions are then found over a wide range of conditions, in the case of free boundaries, by numerical and analytic techniques, in particular by asymptotic and perturbation methods. The results obtained by the different techniques are shown to be in excellent agreement. As for the linear theory, the calculations predict that the simultaneous presence' of a magnetic field and rotation may produce conflicting tendencies.

scholarly journals Several Physical Properties of Two Interacting Complex Scalar Fields at Finite Density

2011 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
Tran Huu Phat ◽  
Phan Thi Duyen
Keyword(s):  
Mean Field ◽  
Scalar Fields ◽  
Meissner Effect ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Goldstone Theorem ◽  
Complex Scalar ◽  
Finite Density ◽  
Chemical Potentials ◽  
The Mean

The two interacting complex scalar fields at finite density is considered in the mean field approximation. It is shown that although the symmetry is spontaneously broken for the chemical potentials bigger than the meson masses in vacuum, but the Goldstone theorem is not preserved in broken phase. Then two mesons are condensed and their condensates turn out to be two-gap superconductor which is signaled by the appearance of the Meissner effect as well as the Abrikosov and non-Abrikosov vortices. Finally, there exhibits domain wall which is the plane, where two condensates flowing in opposite directions collide and generate two types of vortices with cores in the wall.

scholarly journals SU(3) Polyakov linear-sigma model with finite isospin asymmetry: QCD phase diagram

2019 ◽  
Vol 34 (31) ◽  
pp. 1950199 ◽  
Author(s):  
Abdel Nasser Tawfik ◽  
Abdel Magied Diab ◽  
M. T. Ghoneim ◽  
H. Anwer
Keyword(s):  
Phase Structure ◽  
Sigma Model ◽  
Chemical Potential ◽  
Mean Field ◽  
Field Approximation ◽  
Linear Sigma Model ◽  
Dense Medium ◽  
Mean Field Approximation ◽  
Isospin Asymmetry ◽  
Qcd Phase Diagram

The SU(3) Polyakov linear-sigma model (PLSM) in mean-field approximation is utilized in analyzing the chiral condensates [Formula: see text], [Formula: see text], [Formula: see text] and the deconfinement order parameters [Formula: see text], [Formula: see text], at finite isospin asymmetry. The bulk thermodynamics including pressure density, interaction measure, susceptibility and second-order correlations with baryon, strange and electric charge quantum numbers are studied in thermal and dense medium. The PLSM results are confronted to the available lattice quantum chromodynamics (QCD) calculations. The excellent agreement obtained strengthens the reliability of fixing the PLSM parameters and therefore supports further predictions even beyond the scope of the lattice QCD numerical applicability. From the QCD phase structure at finite isospin chemical potential [Formula: see text], we find that the pseudocritical temperatures decrease with the increase in [Formula: see text]. We conclude that the QCD phase structure in [Formula: see text] plane seems to extend the one in [Formula: see text] plane.

Particle Orientational Properties and Viscosity of a Dense Colloidal Dispersion Composed of Ferromagnetic Spherocylinder Particles: Analysis by Means of Mean Field Approximation for a Simple Shear

2005 ◽  
Author(s):  
Akira Satoh
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Mean Field ◽  
Magnetic Interaction ◽  
Colloidal Dispersion ◽  
Field Approximation ◽  
Magnetic Interactions ◽  
Mean Field Approximation ◽  
Particle Interactions ◽  
Orientational Distribution

We have theoretically investigated the particle orientational distribution and viscosity of a dense colloidal dispersion composed of ferromagnetic spherocylinder particles under circumstances of an applied magnetic field. The mean field approximation has been applied to take into account the magnetic interactions of the particle of interest with the other ones which belong to the neighboring clusters, besides its own cluster. The basic equation of the orientational distribution function, which is an integro-differential equation, has approximately been solved by Galerkin’s method and the method of successive approximation. Even when the magnetic interaction between particles is of the order of the thermal energy, the effect of particle-particle interactions on the orientational distribution comes to appear more significantly with increasing the volumetric fraction of particles. This effect comes to appear more significantly when the influence of the applied magnetic field is not relatively so strong compared with magnetic particle-particle interactions.

PULSED SUPERRADIANT EMISSION FROM A MAGNETIC DIPOLE SYSTEM

1993 ◽  
Vol 07 (12) ◽  
pp. 2353-2365
Author(s):  
SALOMON S. MIZRAHI ◽  
MAURO A. MEWES
Keyword(s):  
Magnetic Field ◽  
Single Particle ◽  
Mean Field ◽  
Field Approximation ◽  
Transverse Magnetic ◽  
Time Dependent ◽  
Mean Field Approximation ◽  
Magnetic Dipoles ◽  
Emission Process ◽  
Dipole System

The superradiant emission is considered for a radiating system constituted by N dressed spin-1/2 magnetic dipoles, described by a nonlinear single particle Hamiltonian that is derived under a mean field approximation. This Hamiltonian describes adequately the transient regime of the emission process: The intensity of the radiation follows the sech2 law and its peak is proportional to N2. Then, one considers the application of a periodic time-dependent transverse magnetic field and we study the behavior of the emission that becomes periodically pulsed.

scholarly journals ON A MEAN FIELD APPROXIMATION FOR HIGGS-YUKAWA SYSTEMS

1994 ◽  
Vol 09 (11) ◽  
pp. 983-991 ◽  
Author(s):  
SERGEI V. ZENKIN
Keyword(s):  
Phase Diagram ◽  
Phase Structure ◽  
Finite Lattice ◽  
Mean Field ◽  
Field Approximation ◽  
Ladder Approximation ◽  
Mean Field Approximation ◽  
Ferromagnetic Phase ◽  
Time Dimension ◽  
Infinite Lattice

We discuss the phase structure of a lattice Higgs-Yukawa system in the variational mean field approximation with contributions of fermionic determinant being calculated in a ladder approximation. In particular, we demonstrate that in this approximation the ferromagnetic phase in the Z2 model with naive fermions can appear as an artifact of a finite lattice and that the phase diagram for this model on infinite lattice changes qualitatively at space-time dimension D = 4 compared with those at D > 4.

Influences of Magnetic Particle-Particle Interactions on Orientational Distributions and Rheological Properties of a Semi-Dense Colloidal Dispersion Composed of Rod-Like Hematite Particles: Analysis by Means of Mean Field Approximation for an External Magnetic Field Parallel to the Angular Velocity Vector of a Simple Shear Flow

2007 ◽  
Author(s):  
Ryo Hayasaka ◽  
Masayuki Aoshima ◽  
Toshinori Suzuki ◽  
Akira Satoh
Keyword(s):  
Magnetic Field ◽  
Magnetic Moment ◽  
Mean Field ◽  
Field Approximation ◽  
Field Direction ◽  
Magnetic Interactions ◽  
Mean Field Approximation ◽  
Magnetic Field Direction ◽  
Orientational Distribution ◽  
The Magnetic Field

We have investigated mainly the influences of magnetic particle-particle interactions on orientational distributions and viscosity of a semi-dense dispersion, which is composed of rod-like particles with a magnetic moment magnetized normal to the particle axis. In addition, the influences of the magnetic field strength, shear rate, and random forces on the orientational distribution and rheological properties have been clarified. The mean field approximation has been applied to take into account magnetic interactions between rod-like particles. The basic equation of the orientational distribution function has been derived from the balance of torques and solved by the numerical analysis method. The results obtained here are summarized as follows. For a strong magnetic field, the rotational motion of the rod-like particle is restricted in a plane normal to the shearing plane because the magnetic moment of the particle is restricted in the magnetic field direction. Under circumstances of a very strong magnetic interaction between particles, the magnetic moment is strongly restricted in the magnetic field direction, so that the particle has a tendency to incline in the flow direction with the magnetic moment pointing to the magnetic field direction. For a strong shear flow, a directional characteristic of rod-like particles is enhanced, and this leads to a more significant one-peak-type distribution of the orientational distribution function. Magnetic interactions between particles do not contribute to the viscosity because the mean-field vector has only a component along the magnetic field direction.

scholarly journals THE INFLUENCE OF THE MAGNETIC FIELD ON THE PROPERTIES OF NEUTRON STAR MATTER

2007 ◽  
Vol 22 (07n10) ◽  
pp. 623-629 ◽  
Author(s):  
WEI CHEN ◽  
PU-QING ZHANG ◽  
LIANG-GANG LIU
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Neutron Star Matter ◽  
Density Region ◽  
High Density Region ◽  
The Difference ◽  
The Magnetic Field

In the mean field approximation of the relativistic σ-ω-ρ model, the magnetic fields are incorporated, and it's influence on the properties of n-p-e neutron star matter are studied. When the strength of the magnetic field is weaker than ~1018G, the particles' fractions and chemical potentials, matter's energy density and pressure hardly change with the magnetic field; when the strength of the magnetic field is stronger than ~1020G, the above quantities change with the magnetic field evidently. Furthermore, the pressure is studied in both thermodynamics and hydrodynamics. The difference between these two ways exits in the high density region, that is, the thermal self-consistency may not be satisfied in this region if the magnetic field is considered.

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