Compact Star Equation Of State With Temperature And Magnetic Field Effects

Compact stars (CSs) are the remnants of "dead" stars that were too small to form black holes; the category includes both white dwarfs (WDs) and neutron stars (NSs). To produce a full description of any magnetized compact star requires solving Einstein's equations in unison with Maxwell's equations. However, when putting these two sets of equations together, there is an additional degree of freedom that requires the inclusion of the equation of state (EOS) of the stellar matter in question. The most notable difference between CSs and other stars is that CSs consist of degenerate fermion matter. Fermionic matter exists in a degenerate state when the temperature is low compared to the Fermi energy. Such states arise due to the Pauli exclusion principle, which states that no two identical fermions (particles with half integer spin) in the same quantum system may inhabit the same quantum state. In the case of WDs, this degeneracy is caused solely by electrons; whereas, in NSs, the degeneracy is in several species of particles including neutrons and protons, but also more "exotic" baryons, such as Lambdas, Sigmas, and Cascades. In the grand canonical ensemble, the stellar EOS is typically expressed as the relation between the total energy density of a gas of particles and their pressure. It is calculated using thermodynamics with, in the NS case, an additional contribution from the strong nuclear force, which must be modeled. Due to computational difficulty, the EOS is often calculated in a simplified way, assuming that one aspect or another is not significant. As such, EOSs exist with temperature effects or with magnetic field effects, but not with both. For example, higher temperatures (without additional degrees of freedom) lead to higher pressures at the same energy density; the EOS is "stiffer." Magnetic fields lead to a pressure anisotropy and Landau quantization, which gives rise to De Haas-Van Alphen oscillations in the EOS. This thesis breaks new ground by simultaneously including both temperature and magnetic field effects into the EOS of compact stars. The thermodynamic portion of the EOS is calculated by treating the particles as a relativistic free Fermi gas, in which, particles are treated as non-interacting and must obey Fermi-Dirac statistics. This approach also allows for the calculation of other thermodynamic quantities, such as number density, entropy density, and magnetization. Contributions from the strong force are calculated using the chiral mean field (CMF) model for neutron stars. The CMF model is a relativistic effective model based on a non-linear realization of the linear sigma model of Quantum Chromodynamics (QCD). It features hadron deconfinement into quarks and self-consistent chiral symmetry restoration. Each fundamental force is thought to have a force carrying boson (particles with integer spin, not subject to Pauli exclusion). The photon is the carrier for the electromagnetic force and the carrier for the strong nuclear force is the gluon. In the CMF model, gluons are approximated as "mesons," which are exchanged between hadrons and quarks. As a result, these mesons acquire some properties from both gluons and quarks. Note that, due to the high density and low temperature of NS matter, standard QCD approaches fail to provide an adequate description. Lattice QCD exhibits the sign problem at non-zero baryon density, due to integrating highly oscillating functions. Perturbative QCD breaks down in the presence of strong particle interactions. These are both conditions found in NSs. Finally, this thesis investigates the EOS for isospin-symmetric matter (equal numbers of protons and neutrons or up and down quarks), to reproduce conditions found in heavy ion collisions (HICs). While HICs do not create matter with net density comparable to that of CSs, the energy density is comparable to that of CSs due to their relativistic speeds. This makes HICs the closest we can get to creating CS matter on Earth.

This book focuses on the equation of state (EoS) of compact stars, particularly the intriguing possibility of the “quark star model.” The EoS of compact stars is the subject of ongoing debates among astrophysicists and particle physicists, due to the non-perturbative property of strong interaction at low energy scales. The book investigates the tidal deformability and maximum mass of rotating quark stars and triaxially rotating quark stars, and compares them with those of neutron stars to reveal significant differences. Lastly, by combining the latest observations of GW170817, the book suggests potential ways to distinguish between the neutron star and quark star models.

The book gives an extended review of theoretical and observational aspects of neutron star physics. With masses comparable to that of the Sun and radii of about ten kilometres, neutron stars are the densest stars in the Universe. This book describes all layers of neutron stars, from the surface to the core, with the emphasis on their structure and equation of state. Theories of dense matter are reviewed, and used to construct neutron star models. Hypothetical strange quark stars and possible exotic phases in neutron star cores are also discussed. Also covered are the effects of strong magnetic fields in neutron star envelopes.

This self-contained textbook brings together many different branches of physics--e.g. nuclear physics, solid state physics, particle physics, hydrodynamics, relativity--to analyze compact objects. The latest astronomical data is assessed. Over 250 exercises.

Modern comprehensive introduction and overview of the physics of White Dwarfs, Neutron Stars and Black Holes, including all relevant observations. Contains a basic introduction to General Relativity, including the modern 3+1 split of spacetime and of Einstein’s equations. The split is used for the first time to derive the structure equations for rapidly rotating neutron stars and Black Holes. Detailed discussions and derivations of current theoretical results. In particular also the most recent equations of state for neutron star matter are explained. Topics , such as colour superconductivity are discussed and used for modelling. A book for graduate students and researchers. Contains exercises and some solutions.

The masses of neutron stars are limited by an instability to gravitational collapse and an instability driven by gravitational waves limits their spin. Their oscillations are relevant to x-ray observations of accreting binaries and to gravitational wave observations of neutron stars formed during the coalescence of double neutron-star systems. This volume includes more than forty years of research to provide graduate students and researchers in astrophysics, gravitational physics and astronomy with the first self-contained treatment of the structure, stability and oscillations of rotating neutron stars. This monograph treats the equations of stellar equilibrium; key approximations, including slow rotation and perturbations of spherical and rotating stars; stability theory and its applications, from convective stability to the r-mode instability; and numerical methods for computing equilibrium configurations and the nonlinear evolution of their oscillations. The presentation of fundamental equations, results and applications is accessible to readers who do not need the detailed derivations.

The ideal text for a one-semester course in radio astronomy Essential Radio Astronomy is the only textbook on the subject specifically designed for a one-semester introductory course for advanced undergraduates or graduate students in astronomy and astrophysics. It starts from first principles in order to fill gaps in students' backgrounds, make teaching easier for professors who are not expert radio astronomers, and provide a useful reference to the essential equations used by practitioners. This unique textbook reflects the fact that students of multiwavelength astronomy typically can afford to spend only one semester studying the observational techniques particular to each wavelength band. Essential Radio Astronomy presents only the most crucial concepts—succinctly and accessibly. It covers the general principles behind radio telescopes, receivers, and digital backends without getting bogged down in engineering details. Emphasizing the physical processes in radio sources, the book's approach is shaped by the view that radio astrophysics owes more to thermodynamics than electromagnetism. Proven in the classroom and generously illustrated throughout, Essential Radio Astronomy is an invaluable resource for students and researchers alike. The only textbook specifically designed for a one-semester course in radio astronomy Starts from first principles Makes teaching easier for astronomy professors who are not expert radio astronomers Emphasizes the physical processes in radio sources Covers the principles behind radio telescopes and receivers Provides the essential equations and fundamental constants used by practitioners Supplementary website includes lecture notes, problem sets, exams, and links to interactive demonstrations An online illustration package is available to professors

This book summarizes the recent progress in the physics and astrophysics of neutron stars and, most importantly, it identifies and develops effective strategies to explore, both theoretically and observationally, the many remaining open questions in the field. Because of its significance in the solution of many fundamental questions in nuclear physics, astrophysics and gravitational physics, the study of neutron stars has seen enormous progress over the last years and has been very successful in improving our understanding in these fascinating compact objects. The book addresses a wide spectrum of readers, from students to senior researchers. Thirteen chapters written by internationally renowned experts offer a thorough overview of the various facets of this interdisciplinary science, from neutron star formation in supernovae, pulsars, equations of state super dense matter, gravitational wave emission, to alternative theories of gravity. The book was initiated by the European Cooperation in Science and Technology (COST) Action MP1304 “Exploring fundamental physics with compact stars” (NewCompStar).

Includes bibliographical references and index.