RANDOM JOSEPHSON NETWORKS AND SPIN GLASSES

1987 ◽  
Vol 01 (01n02) ◽  
pp. 27-37 ◽  
Author(s):  
M.V. FEIGEL’MAN ◽  
L.B. IOFFE ◽  
A.I. LARKIN ◽  
V.M. VINOKUR
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Numerical Simulations ◽  
Spin Glass ◽  
Spin Glasses ◽  
Equations Of State ◽  
Analytical Theory ◽  
Diamagnetic Response ◽  
The Magnetic Field

The phase transition into a spin glass-like state is predicted for the system of superconductive wires connected by Josephson links and placed into the magnetic field. History-dependent equations of state for T<Tc are derived and diamagnetic response to the variation of the magnetic field is predicted. The experiments that can solve the discrepancy between the analytical theory and the numerical simulations on the existence of the phase transition in the vector spin glasses are discussed.

QUARK MATTER MAGNETIZATION: PHASE TRANSITION OR UPPER LIMIT OF MAGNETIC FIELD?

2007 ◽  
Vol 16 (02n03) ◽  
pp. 255-260 ◽  
Author(s):  
A. PÉREZ MARTÍNEZ ◽  
H. PÉREZ ROJAS ◽  
H. J. MOSQUERA CUESTA ◽  
M. ORSARIA
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quark Matter ◽  
Equations Of State ◽  
Electromagnetic Interaction ◽  
Stellar Objects ◽  
Strong Magnetic Fields ◽  
Quark Stars ◽  
Mit Bag Model ◽  
The Magnetic Field

Quark matter is expected to exist in the interior of compact stellar objects as neutron stars or even the more exotic strange stars. In a previous paper [Int. J. Mod. Phys. D14(11) (2005) 1959], the equations of state for a degenerate quark gas were studied in the presence of ultra strong magnetic fields, starting from the modified MIT Bag Model which included the electromagnetic interaction. In the present paper, we revise the behavior of a system made up of quarks with anomalous magnetic moment (AMM) and we discuss its effect in terms of the magnetization and susceptibility. It can be understood as a phase transition or as a criterion of the limited value for the magnetic field in quark stars.

scholarly journals Magnetorotational Mechanism of Supernova Explosions - Results of 2D Simulations

1998 ◽  
Vol 11 (1) ◽  
pp. 376-376
Author(s):  
S.G. Moiseenko
Keyword(s):  
Magnetic Field ◽  
Equations Of State ◽  
Supernova Explosion ◽  
Neutrino Energy ◽  
Energy Losses ◽  
Rotational Momentum ◽  
Supernova Explosions ◽  
2D Numerical Simulation ◽  
Lagrangian Scheme ◽  
The Magnetic Field

Results of 2D numerical simulation of the magneto rotational mechanism of a supernova explosion are presented. Simulation has been done for the real equations of state and neutrino energy losses have been taken into account. Simulation has been done on the basis of an Implicit Lagrangian scheme on atriangular grid with grid reconstructuring. It is shown that, due to differential rotation of the star, a toroidal component of the magnetic field appears and grows with time. Rotational momentum transfers outwards as the toroidal component grows with time. With the evolution of the process, part of the envelope of the star is ejected. The amounts of the thrown-off mass and energy are estimated. The results of the simulation could be used as a possible explanation for the supernova explosion picture.

Dynamics of a disc in a nematic liquid crystal

Soft Matter ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1279-1294 ◽  
Author(s):  
Alena Antipova ◽  
Colin Denniston
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Numerical Simulations ◽  
Nematic Liquid Crystal ◽  
Weak Magnetic Field ◽  
Angular Speed ◽  
The Magnetic Field

We explain the motion of a micron-sized ferromagnetic disc immersed in a nematic liquid crystal under the action of a weak magnetic field using numerical simulations. We show that the disc's behaviour can be controlled by the angular speed of the magnetic field and its magnitude.

scholarly journals Existence of a Phase Transition under Finite Magnetic Field in the Long-Range RKKY Ising Spin Glass DyxY1-xRu2Si2

2010 ◽  
Vol 79 (12) ◽  
pp. 123704 ◽  
Author(s):  
Yoshikazu Tabata ◽  
Kousuke Matsuda ◽  
Satoshi Kanada ◽  
Teruo Yamazaki ◽  
Takeshi Waki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Spin Glass ◽  
Long Range ◽  
Ising Spin Glass ◽  
Ising Spin

Dynamical phase transition of spin glasses in a magnetic field

1989 ◽  
Vol 22 (21) ◽  
pp. 4659-4664 ◽  
Author(s):  
L de Arcangelis ◽  
H J Herrmann ◽  
A Coniglio
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Spin Glasses ◽  
Dynamical Phase Transition ◽  
Dynamical Phase

scholarly journals Estimation of Electrical Conductivity and Magnetization Parameter of Neutron Star Crusts and Applied to the High-Braking-Index Pulsar PSR J1640-4631

Universe ◽  
2020 ◽  
Vol 6 (5) ◽  
pp. 63
Author(s):  
Hui Wang ◽  
Zhi-Fu Gao ◽  
Huan-Yu Jia ◽  
Na Wang ◽  
Xiang-Dong Li
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Neutron Stars ◽  
General Expression ◽  
Equations Of State ◽  
Rotation Period ◽  
Ohmic Dissipation ◽  
Hartree Fock ◽  
Induction Equation ◽  
The Magnetic Field

Young pulsars are thought to be highly magnetized neutron stars (NSs). The crustal magnetic field of a NS usually decays at different timescales in the forms of Hall drift and Ohmic dissipation. The magnetization parameter ω B τ is defined as the ratio of the Ohmic timescale τ O h m to the Hall drift timescale τ H a l l . During the first several million years, the inner temperature of the newly born neutron star cools from T = 10 9 K to T = 1.0 × 10 8 K, and the crustal conductivity increases by three orders of magnitude. In this work, we adopt a unified equations of state for cold non-accreting neutron stars with the Hartree–Fock–Bogoliubov method, developed by Pearson et al. (2018), and choose two fiducial dipole magnetic fields of B = 1.0 × 10 13 G and B = 1.0 × 10 14 G, four different temperatures, T, and two different impurity concentration parameters, Q, and then calculate the conductivity of the inner crust of NSs and give a general expression of magnetization parameter for young pulsars: ω B τ ≃ ( 1 − 50 ) B 0 / ( 10 13 G) by using numerical simulations. It was found when B ≤ 10 15 G, due to the quantum effects, the conductivity increases slightly with the increase in the magnetic field, the enhanced magnetic field has a small effect on the matter in the low-density regions of the crust, and almost has no influence the matter in the high-density regions. Then, we apply the general expression of the magnetization parameter to the high braking-index pulsar PSR J1640-4631. By combining the observed arrival time parameters of PSR J1640-4631 with the magnetic induction equation, we estimated the initial rotation period P 0 , the initial dipole magnetic field B 0 , the Ohm dissipation timescale τ O h m and Hall drift timescale τ H a l l . We model the magnetic field evolution and the braking-index evolution of the pulsar and compare the results with its observations. It is expected that the results of this paper can be applied to more young pulsars.

CHIRAL ORDER IN SPIN GLASSES

1996 ◽  
Vol 07 (03) ◽  
pp. 345-353 ◽  
Author(s):  
HIKARU KAWAMURA
Keyword(s):  
Numerical Simulations ◽  
Spin Glass ◽  
Spin Glasses ◽  
Spin Rotation ◽  
Reflection Symmetry ◽  
The Novel ◽  
Glass Transitions ◽  
Rotation Symmetry ◽  
Numerical Evidence ◽  
Chiral Glass

The results of the recent numerical simulations on vector spin glasses are presented. Numerical evidence of the novel chiral-glass state, accompanied with broken spin-reflection symmetry with preserving spin-rotation symmetry, is presented. Implication to experiments on spin-glass transitions is discussed.

scholarly journals Magnetorotational supernovae with different equations of state

2011 ◽  
Vol 7 (S279) ◽  
pp. 357-358
Author(s):  
Sergey G. Moiseenko ◽  
Gennady S. Bisnovatyi-Kogan
Keyword(s):  
Magnetic Field ◽  
Shock Wave ◽  
Angular Momentum ◽  
Differential Rotation ◽  
Equations Of State ◽  
Supernova Explosion ◽  
Explosion Energy ◽  
Iron Core ◽  
Wave Forms ◽  
The Magnetic Field

AbstractWe present results of the simulation of a magneto-rotational supernova explosion. We show that, due to the differential rotation of the collapsing iron core, the magnetic field increases with time. The magnetic field transfers angular momentum and a MHD shock wave forms. This shock wave produces the supernova explosion. The explosion energy computed in our simulations is 0.5-2.5 ċ 1051erg. We used two different equations of state for the simulations. The results are rather similar.

SPECTRAL PROPERTIES AND SYMMETRIES OF DOUBLE COVERINGS OF GRAPHS WITH APPLICATIONS TO SUPERCONDUCTIVITY

2005 ◽  
Vol 15 (02) ◽  
pp. 301-324
Author(s):  
JACOB RUBINSTEIN ◽  
MICHELLE SCHATZMAN
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Phase Transitions ◽  
Ground State ◽  
Spectral Properties ◽  
Embedded Graph ◽  
Symmetry Constraints ◽  
The Laplace Operator ◽  
The Magnetic Field ◽  
Double Coverings

Let M be a planar embedded graph, and let [Formula: see text] be its double covering. We count the multiplicity of the ground states of the Laplace operator on [Formula: see text] under certain symmetry constraints. The examples of interest for us are ladder-like graphs made out of n, identical rectangles. We find that in the case of an odd n, the multiplicity of the ground state is 2, and if n, is even, the ground state is simple. This result gives an answer to a conjecture by Parks on the type of phase transitions that can occur in a superconducting ladder: Parks conjectured that in the case when the magnetic field is one half fluxoid per rectangle, the phase transition would be continuous in the case of a ladder made out of two rectangles. Our result indeed implies Parks conjecture and generalizes it to any even ladder. The mathematics of this paper is a mixture of topology, symmetry arguments and comparison theorem between the eigenvalues of Laplace operators on graphs with well chosen boundary conditions.

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