Magnetic fields in neutron stars: A theoretical perspective

Reisenegger, Andreas; Prieto, J.; Benguria, Rafael D.; Lai, Dong; Araya, Pablo A.

doi:10.1063/1.2077190

Cited by 10 publications

(7 citation statements)

References 33 publications

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“…Thus it is natural that a large amount of work has been devoted to the study of neutron star magnetic field evolution. Recent reviews include Bhattacharya and Srinivasan (1995), Ruderman (2004) and Reisenegger et al (2005).…”

Section: Neutron Star Magnetic Field Evolutionmentioning

confidence: 99%

Physics of strongly magnetized neutron stars

Harding¹,

Lai²

2006

Rep. Prog. Phys.

820

763

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Abstract. There has recently been growing evidence for the existence of neutron stars possessing magnetic fields with strengths that exceed the quantum critical field strength of 4.4 × 10 13 G, at which the cyclotron energy equals the electron rest mass. Such evidence has been provided by new discoveries of radio pulsars having very high spin-down rates and by observations of bursting gamma-ray sources termed magnetars. This article will discuss the exotic physics of this high-field regime, where a new array of processes becomes possible and even dominant, and where familiar processes acquire unusual properties. We review the physical processes that are important in neutron star interiors and magnetospheres, including the behavior of free particles, atoms, molecules, plasma and condensed matter in strong magnetic fields, photon propagation in magnetized plasmas, free-particle radiative processes, the physics of neutron star interiors, and field evolution and decay mechanisms. Application of such processes in astrophysical source models, including rotation-powered pulsars, soft gamma-ray repeaters, anomalous X-ray pulsars and accreting X-ray pulsars will also be discussed. Throughout this review, we will highlight the observational signatures of high magnetic field processes, as well as the theoretical issues that remain to be understood.

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Section: Neutron Star Magnetic Field Evolutionmentioning

confidence: 99%

Physics of strongly magnetized neutron stars

Harding¹,

Lai²

2006

Rep. Prog. Phys.

820

763

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“…The resonance frequencies correspond to fields B ∼ 1.4 x 10 12 G [25]. In isolated pulsars, the field is usually derived from the relation between the period of rotation P and its time rate of changeṖ, assuming magnetic dipole radiation, using the formalism detailed in [3], which gives rise to Equation 2.…”

Section: Mechanisms Of Pulsar Magnetismmentioning

confidence: 99%

Braking index of isolated pulsars. II. A novel two-dipole model of pulsar magnetism

Hamil

Stone

2016

Phys. Rev. D

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The magnetic dipole radiation (MDR) model is currently the best approach we have to explain pulsar radiation. However a most characteristic parameter of the observed radiation, the braking index n obs shows deviations for all the eight best studied isolated pulsars, from the simple model prediction n dip = 3. The index depends upon the rotational frequency and its first and second time derivatives, but also on the assumption of that the magnetic dipole moment and inclination angle, and the moment of inertia of the pulsar are constant in time. In a recent paper [Phys. Rev. D 91, 063007 (2015)] we showed conclusively that changes in the moment of inertia with frequency alone, cannot explain the observed braking indices.Possible observational evidence for the magnetic dipole moment migrating away from the rotational axis at a rateα ∼ 0.6 • per 100 years over the life time of the Crab pulsar has been recently suggested by Lyne et al. In this paper, we explore the MDR model with constant moment of inertia and magnetic dipole moment but variable inclination angle α. We first discuss the effect of the variation of α on the observed braking indices and show they all can be understood. However, no explanation for the origin of the change in α is provided.After discussion of the possible source(s) of magnetism in pulsars we propose a simple mechanism for the change in α based on a toy model in which the magnetic structure in pulsars consists of two interacting dipoles. We show that such a system can explain the Crab observation and the measured braking indices.

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“…These are the so-called Schwinger scale values [2] and they are enormous on the laboratory scale. Such electric and magnetic fields exist in heavy ion collisions [3] and in neutron stars [4], respectively. Nevertheless, low order nonlinear QED effects have been observed in the laboratory, such as (i) the elastic scattering of a photon from the Coulomb field of a nucleus and (ii) the photon splitting into two photons in the Coulomb field [5].…”

mentioning

confidence: 99%

Nonlinear Quantum Electrodynamics in Dirac Materials

2022

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Classical electromagnetism is linear. However, fields can polarize the vacuum Dirac sea, causing quantum nonlinear electromagnetic phenomena, e.g., scattering and splitting of photons that occur only in very strong fields found in neutron stars or heavy ion colliders. We show that strong nonlinearity arises in Dirac materials at much lower fields ∼ 1T, allowing us to explore the extremely high field limit of quantum electrodynamics in solids. We explain recent experiments in a unified framework and predict nonlinear magneto-electric response, including a magnetic enhancement of dielectric constant and electrically induced magnetization. We propose experiments and discuss the applications on novel materials.

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Magnetic fields in neutron stars: A theoretical perspective

Cited by 10 publications

References 33 publications

Physics of strongly magnetized neutron stars

Physics of strongly magnetized neutron stars

Braking index of isolated pulsars. II. A novel two-dipole model of pulsar magnetism

Nonlinear Quantum Electrodynamics in Dirac Materials

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