Travelling fronts in nonlocal models for phase separation in an external field

1997 ◽  
Vol 127 (4) ◽  
pp. 823-835 ◽  
Author(s):  
Enza Orlandi ◽  
Livio Triolo
Keyword(s):  
Magnetic Field ◽  
Metastable Phase ◽  
Glauber Dynamics ◽  
One Dimensional ◽  
Kac Potentials ◽  
Nonlocal Models ◽  
Nonlocal Evolution Equation ◽  
Travelling Fronts ◽  
The One ◽  
The Magnetic Field

We consider the one-dimensional, nonlocal, evolution equation derived by De Masi et al. (1995) for Ising systems with Glauber dynamics, Kac potentials and magnetic field. We prove the existence of travelling fronts, their uniqueness modulo translations among the monotone profiles and their linear stability for all the admissible values of the magnetic field for which the underlying spin system exhibits a stable and metastable phase.

Staggered-field effect on the magnetic-field-induced magnetization of the one-dimensional antiferromagnetYb4As3

2002 ◽  
Vol 65 (5) ◽  
Author(s):  
Kazuaki Iwasa ◽  
Masahumi Kohgi ◽  
Arsen Gukasov ◽  
Jean-Michel Mignot ◽  
Naokazu Shibata ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
One Dimensional ◽  
The One ◽  
The Magnetic Field

Ultrasonic wave generation in two-band organic conductors due to thermoelectric effect

2017 ◽  
Vol 31 (31) ◽  
pp. 1750250 ◽  
Author(s):  
Danica Krstovska
Keyword(s):  
Magnetic Field ◽  
Ultrasonic Wave ◽  
Organic Conductors ◽  
Wave Generation ◽  
Charge Carriers ◽  
One Dimensional ◽  
Temperature Dependences ◽  
The One ◽  
Longitudinal Ultrasonic Wave ◽  
The Magnetic Field

A linear thermoelectric generation of a longitudinal ultrasonic wave in organic conductors with two conducting channels, quasi-one dimensional (q1D) and quasi-two dimensional (q2D), is investigated theoretically. The magnetic field and temperature dependences of the amplitude of generated through Nernst effect wave in [Formula: see text]-(BEDT-TTF)2KHg(SCN)4 for two boundary conditions, isothermal and adiabatic are obtained. Findings show a preference of one type of a boundary over another in the wave generation and propagation depending on the magnetic field strength and temperature. At lower temperatures and above B[Formula: see text]=[Formula: see text]4 T, the wave amplitude for adiabatic boundary is smaller compared to the one for isothermal boundary although there is a heat flux through the conductor’s surface in the latter. Both the q1D and q2D charge carriers contribute to the observation of the effect but with different magnitude due to the different drift velocity along the direction of wave propagation.

scholarly journals Effective Hamiltonian for a half-filled asymmetric ionic Hubbard chain with alternating on-site interaction

2016 ◽  
Vol 30 (03) ◽  
pp. 1550260 ◽  
Author(s):  
I. Grusha ◽  
M. Menteshashvili ◽  
G. I. Japaridze
Keyword(s):  
Magnetic Field ◽  
Nearest Neighbor ◽  
Effective Hamiltonian ◽  
Heisenberg Chain ◽  
Spin Hamiltonian ◽  
Effective Spin ◽  
One Dimensional ◽  
The One ◽  
Strong Repulsion ◽  
Ionic Hubbard Model

We derive an effective spin Hamiltonian for the one-dimensional half-filled asymmetric ionic Hubbard model (IHM) with alternating on-site interaction in the limit of strong repulsion. It is shown that the effective Hamiltonian is that of a spin S = 1/2 anisotropic XXZ Heisenberg chain with alternating next-nearest-neighbor (NNN) and three-spin couplings in the presence of a uniform and a staggered magnetic field.

scholarly journals The influence of resistivity gradients on shock conditions for a Petschek reconnection geometry

2016 ◽  
Vol 34 (4) ◽  
pp. 421-425
Author(s):  
Christian Nabert ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Magnetic Field ◽  
Necessary Conditions ◽  
The Other ◽  
Diffusion Region ◽  
Two Dimensional ◽  
Characteristic Velocity ◽  
Magnetohydrodynamic Equations ◽  
One Dimensional ◽  
The Magnetic Field ◽  
Alfven Velocity

Abstract. Shock waves can strongly influence magnetic reconnection as seen by the slow shocks attached to the diffusion region in Petschek reconnection. We derive necessary conditions for such shocks in a nonuniform resistive magnetohydrodynamic plasma and discuss them with respect to the slow shocks in Petschek reconnection. Expressions for the spatial variation of the velocity and the magnetic field are derived by rearranging terms of the resistive magnetohydrodynamic equations without solving them. These expressions contain removable singularities if the flow velocity of the plasma equals a certain characteristic velocity depending on the other flow quantities. Such a singularity can be related to the strong spatial variations across a shock. In contrast to the analysis of Rankine–Hugoniot relations, the investigation of these singularities allows us to take the finite resistivity into account. Starting from considering perpendicular shocks in a simplified one-dimensional geometry to introduce the approach, shock conditions for a more general two-dimensional situation are derived. Then the latter relations are limited to an incompressible plasma to consider the subcritical slow shocks of Petschek reconnection. A gradient of the resistivity significantly modifies the characteristic velocity of wave propagation. The corresponding relations show that a gradient of the resistivity can lower the characteristic Alfvén velocity to an effective Alfvén velocity. This can strongly impact the conditions for shocks in a Petschek reconnection geometry.

Application of the Landau-Luttinger Liquid Formulation to the Study of the Magnetic Properties of the 1-D Hubbard Model

1991 ◽  
Vol 05 (01n02) ◽  
pp. 3-30 ◽  
Author(s):  
J. Carmelo ◽  
P. Horsch ◽  
P.A. Bares ◽  
A.A. Ovchinnikov
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Hubbard Model ◽  
Luttinger Liquid ◽  
Liquid Formulation ◽  
One Dimensional ◽  
Spin Excitations ◽  
Arbitrary Strength ◽  
The One

The Landau-Luttinger liquid formulation is used to investigate the physics of the one-dimensional Hubbard model in a magnetic field of arbitrary strength H. The low lying charge and spin excitations are studied. A novel branch of sound wave-like spin excitations arises for H>0. The low temperature thermodynamics is considered in some detail.

scholarly journals Rotating Melvin-like Universes and Wormholes in General Relativity

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1306
Author(s):  
Kirill Bronnikov ◽  
Vladimir Krechet ◽  
Vadim Oshurko
Keyword(s):  
Magnetic Field ◽  
General Relativity ◽  
Equation Of State ◽  
Symmetry Axis ◽  
Energy Condition ◽  
Flat Space ◽  
Stiff Matter ◽  
Cylindrically Symmetric ◽  
The One ◽  
The Magnetic Field

We find a family of exact solutions to the Einstein–Maxwell equations for rotating cylindrically symmetric distributions of a perfect fluid with the equation of state p=wρ (|w|<1), carrying a circular electric current in the angular direction. This current creates a magnetic field along the z axis. Some of the solutions describe geometries resembling that of Melvin’s static magnetic universe and contain a regular symmetry axis, while some others (in the case w>0) describe traversable wormhole geometries which do not contain a symmetry axis. Unlike Melvin’s solution, those with rotation and a magnetic field cannot be vacuum and require a current. The wormhole solutions admit matching with flat-space regions on both sides of the throat, thus forming a cylindrical wormhole configuration potentially visible for distant observers residing in flat or weakly curved parts of space. The thin shells, located at junctions between the inner (wormhole) and outer (flat) regions, consist of matter satisfying the Weak Energy Condition under a proper choice of the free parameters of the model, which thus forms new examples of phantom-free wormhole models in general relativity. In the limit w→1, the magnetic field tends to zero, and the wormhole model tends to the one obtained previously, where the source of gravity is stiff matter with the equation of state p=ρ.

On the minimizers of the Ginzburg–Landau energy for high kappa: the one-dimensional case

1997 ◽  
Vol 8 (4) ◽  
pp. 331-345 ◽  
Author(s):  
AMANDINE AFTALION
Keyword(s):  
Magnetic Field ◽  
Asymptotic Behaviour ◽  
Dimensional Case ◽  
Numerical Computations ◽  
Ginzburg Landau ◽  
Landau Model ◽  
One Dimensional ◽  
Landau Parameter ◽  
Convergence Results ◽  
The One

The Ginzburg–Landau model for superconductivity is examined in the one-dimensional case. First, putting the Ginzburg–Landau parameter κ formally equal to infinity, the existence of a minimizer of this reduced Ginzburg–Landau energy is proved. Then asymptotic behaviour for large κ of minimizers of the full Ginzburg–Landau energy is analysed and different convergence results are obtained, according to the exterior magnetic field. Numerical computations illustrate the various behaviours.

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