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 MASS–RADIUS RELATION FOR MAGNETIZED STRANGE QUARKS STARS

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1511-1519 ◽  
Author(s):  
A. P. MARTÍNEZ ◽  
R. G. FELIPE ◽  
D. M. PARET
Keyword(s):  
Magnetic Field ◽  
Quark Matter ◽  
Strange Quark ◽  
Baryon Density ◽  
Strange Quark Matter ◽  
Strange Quarks ◽  
Quark Stars ◽  
Mit Bag Model ◽  
The Stability ◽  
The Magnetic Field

We review the stability of magnetized strange quark matter (MSQM) within the phenomenological MIT bag model, taking into account the variation of the relevant input parameters, namely, the strange quark mass, baryon density, magnetic field and bag parameter. A comparison with magnetized asymmetric quark matter in β-equilibrium as well as with strange quark matter (SQM) is presented. We obtain that the energy per baryon for MSQM decreases as the magnetic field increases, and its minimum value at vanishing pressure is lower than the value found for SQM, which implies that MSQM is more stable than non-magnetized SQM. The mass–radius relation for magnetized strange quark stars is also obtained in this framework.

MAGNETIC FIELD AND TEMPERATURE EFFECTS ON STRANGELETS

2011 ◽  
Vol 20 (supp02) ◽  
pp. 42-49
Author(s):  
ERNESTO LÓPEZ FUNE ◽  
AURORA PÉREZ MARTÍNEZ ◽  
DARYEL MANREZA PARET ◽  
RICARDO GONZÁLEZ FELIPE
Keyword(s):  
Magnetic Field ◽  
Electric Charge ◽  
Quark Matter ◽  
Temperature Effects ◽  
Strange Quark ◽  
Strange Quark Matter ◽  
Mit Bag Model ◽  
Phase Temperature ◽  
Matter Phase ◽  
The Magnetic Field

The main properties of magnetized strangelets, namely, their energy per baryon, radius and electric charge, are studied in the unpaired strange quark matter phase. Temperature effects are taken into account in order to study their stability compared to the 56Fe isotope and non-magnetized strangelets within the framework of the MIT bag model. It is concluded that the presence of a magnetic field tends to stabilize more the strangelets, even when temperature is considered. We find that the electric charge is modified in the presence of the magnetic field, leading to higher charge values for magnetized strangelets, when compared to the non-magnetized case.

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.

scholarly journals COMPACT STARS AND MAGNETIZED CFL MATTER

2011 ◽  
Vol 20 (supp02) ◽  
pp. 84-92 ◽  
Author(s):  
AURORA PÉREZ MARTíNEZ ◽  
RICARDO GONZÁLEZ FELIPE ◽  
DARYEL MANREZA PARET
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Ground State ◽  
Quark Matter ◽  
Strange Quark ◽  
Strange Quark Matter ◽  
Compact Stars ◽  
Mit Bag Model ◽  
The Stability ◽  
The Magnetic Field

The stability of the color flavor locked phase in the presence of a strong magnetic field is investigated within the phenomenological MIT bag model. It is found that the minimum value of the energy per baryon in a color flavor locked state at vanishing pressure is lower than the corresponding one for unpaired magnetized strange quark matter and, as the magnetic field increases, the energy per baryon decreases. This implies that magnetized color flavor locked matter is more stable and could become the ground state inside neutron stars. The anisotropy of the pressures is discussed. The mass-radius relation for such stars is also studied.

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.

scholarly journals Effects of Anisotropy on Strongly Magnetized Neutron and Strange Quark Stars in General Relativity

2021 ◽  
Vol 922 (2) ◽  
pp. 149
Author(s):  
Debabrata Deb ◽  
Banibrata Mukhopadhyay ◽  
Fridolin Weber
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Strange Quark ◽  
Radial Direction ◽  
Hydrostatic Equilibrium ◽  
Transverse Orientation ◽  
Quark Stars ◽  
Anisotropic Force ◽  
Local Magnetic Fields ◽  
The Magnetic Field

Abstract We investigate the properties of anisotropic, spherically symmetric compact stars, especially neutron stars (NSs) and strange quark stars (SQSs), made of strongly magnetized matter. The NSs are described by the SLy equation of state (EOS) and the SQSs by an EOS based on the MIT Bag model. The stellar models are based on an a priori assumed density dependence of the magnetic field and thus anisotropy. Our study shows that not only the presence of a strong magnetic field and anisotropy, but also the orientation of the magnetic field itself, have an important influence on the physical properties of stars. Two possible magnetic field orientations are considered: a radial orientation where the local magnetic fields point in the radial direction, and a transverse orientation, where the local magnetic fields are perpendicular to the radial direction. Interestingly, we find that for a transverse orientation of the magnetic field, the stars become more massive with increasing anisotropy and magnetic-field strength and increase in size since the repulsive, effective anisotropic force increases in this case. In the case of a radially oriented magnetic field, however, the masses and radii of the stars decrease with increasing magnetic-field strength because of the decreasing effective anisotropic force. Importantly, we also show that in order to achieve hydrostatic equilibrium configurations of magnetized matter, it is essential to account for both the local anisotropy effects as well as the anisotropy effects caused by a strong magnetic field. Otherwise, hydrostatic equilibrium is not achieved for magnetized stellar models.

EFFECT OF MAGNETIC FIELD ON THE PHASE TRANSITION FROM NUCLEAR MATTER TO QUARK MATTER DURING PROTO-NEUTRON STAR EVOLUTION

2002 ◽  
Vol 11 (04) ◽  
pp. 545-559 ◽  
Author(s):  
V. K. GUPTA ◽  
ASHA GUPTA ◽  
S. SINGH ◽  
J. D. ANAND
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quark Matter ◽  
Mean Field Theory ◽  
Mean Field ◽  
Relativistic Mean Field ◽  
Electron Neutrinos ◽  
Hadron Phase ◽  
Frame Work ◽  
Trapped Electron

We have studied phase transition from hadron matter to quark matter in the presence of high magnetic fields incorporating the trapped electron neutrinos at finite temperatures. We have used the density dependent quark mass (DDQM) model for the quark phase while the hadron phase is treated in the frame-work of relativistic mean field theory. It is seen that the energy density in the hadron phase at phase transition decreases with both magnetic field and temperature.

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.

scholarly journals Photons in a cold axion background and strong magnetic fields: Polarimetric consequences

2015 ◽  
Vol 30 (17) ◽  
pp. 1550099 ◽  
Author(s):  
Domènec Espriu ◽  
Albert Renau
Keyword(s):  
Magnetic Field ◽  
Dark Matter ◽  
Galactic Halo ◽  
Local Density ◽  
Polarization Plane ◽  
Strong Magnetic Fields ◽  
Two Photon ◽  
Main Effect ◽  
Optical Table ◽  
The Magnetic Field

In this work, we analyze the propagation of photons in an environment where a strong magnetic field (perpendicular to the photon momenta) coexists with an oscillating cold axion background with the characteristics expected from dark matter in the galactic halo. Qualitatively, the main effect of the combined background is to produce a three-way mixing among the two photon polarizations and the axion. It is interesting to note that in spite of the extremely weak interaction of photons with the cold axion background, its effects compete with those coming from the magnetic field in some regions of the parameter space. We determine (with one plausible simplification) the proper frequencies and eigenvectors as well as the corresponding photon ellipticity and induced rotation of the polarization plane that depend both on the magnetic field and the local density of axions. We also comment on the possibility that some of the predicted effects could be measured in optical table-top experiments.

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