scholarly journals Nonradial oscillation modes of compact stars with a crust

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Cesar Vásquez Flores ◽  
Zack B. Hall ◽  
Prashanth Jaikumar
Keyword(s):  
Compact Stars ◽  
Oscillation Modes ◽  
Nonradial Oscillation

scholarly journals Acoustic modes of pulsating axion stars: Nonradial oscillations

2019 ◽  
Vol 28 (09) ◽  
pp. 1950111 ◽  
Author(s):  
Grigoris Panotopoulos ◽  
Ilídio Lopes
Keyword(s):  
Effective Potential ◽  
Small Frequency ◽  
Acoustic Modes ◽  
Oscillation Modes ◽  
Nonradial Oscillation ◽  
Nonradial Oscillations

We compute the lowest frequency nonradial oscillation modes of dilute axion stars. The effective potential that enters into the Schrödinger-like equation, several associated eigenfunctions and the large as well as the small frequency separations are shown as well.

scholarly journals NEUTRON STAR MATTER EQUATION OF STATE AND GRAVITATIONAL WAVE EMISSION

2005 ◽  
Vol 20 (31) ◽  
pp. 2335-2349 ◽  
Author(s):  
OMAR BENHAR
Keyword(s):  
Experimental Study ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Neutron Star Matter ◽  
Oscillation Modes ◽  
Nonradial Oscillation ◽  
Macroscopic Objects ◽  
Wave Emission

The EOS of strongly interacting matter at densities ten to fifteen orders of magnitude larger than the typical density of terrestrial macroscopic objects determines a number of neutron star properties, including the pattern of gravitational waves emitted following the excitation of nonradial oscillation modes. This paper reviews some of the approaches employed to model neutron star matter, as well as the prospects for obtaining new insights from the experimental study of gravitational waves emitted by neutron stars.

scholarly journals Quadratic and Cubic Couplings of Oscillation Modes of Stars

1995 ◽  
Vol 155 ◽  
pp. 287-288
Author(s):  
T. Van Hoolst
Keyword(s):  
Main Sequence ◽  
Oscillation Mode ◽  
The Self ◽  
Nonlinear Interactions ◽  
Nonlinear Coupling ◽  
Coupling Coefficients ◽  
Main Sequence Stars ◽  
Evolved Stars ◽  
Oscillation Modes ◽  
Nonradial Oscillation

The strength of nonlinear interactions of oscillation modes of stars is determined by the amplitudes as well as by the eigenfunctions of the oscillation modes. The intrinsic couplings of modes through their eigenfunctions can be described by coupling coefficients. Here, we concentrate on quadratic and cubic coupling coefficients that describe the nonlinear coupling of modes with itself and are called self-coupling coefficients.We considered radial and nonradial oscillation modes of polytropic models with degrees of central condensation that correspond to central condensations of main sequence stars to highly condensed evolved stars. We study the influence of the radial order and the degree of the oscillation mode on the self- coupling coefficients.

scholarly journals Discontinuity Modes in Polytropes

1989 ◽  
Vol 111 ◽  
pp. 254-254
Author(s):  
Bradley W. Carroll
Keyword(s):  
Large Amplitude ◽  
Solar Mass ◽  
Mode Spectrum ◽  
Density Discontinuity ◽  
Fractional Density ◽  
Stellar Pulsation ◽  
Oscillation Modes ◽  
Nonradial Oscillation ◽  
Small Density ◽  
Avoided Crossings

AbstractIn the calculation of linear nonradial oscillation modes in composite polytropes with a small density discontinuity, a discontinuity mode may occur. This mode consists of a wave propagating along the discontinuity interface with a large amplitude that declines exponentially away from the interface. The period P of this mode is well-estimated (to within 10%) bywhere Δρ/<ρ> is the fractional density discontinuity and k is the horizontal wavenumber (c.f. Gabriel and Scuflaire 1980, in Nonradial and Nonlinear Stellar Pulsation, eds. H. Hill and W. Dziembowski, Springer-Verlag). For a 12 solar-mass polytrope with a radius of 4.27 R⊙, a 3% density discontinuity at fractional radius 0.15 produces a discontinuity mode with a period of 7.329 hours. As the density discontinuity increases the period P decreases, resulting in avoided crossings with the normal g-mode spectrum. Between these avoided crossings, the discontinuity mode has an unusually large amplitude at the location of the discontinuity.

scholarly journals Relativistic Cowling approximation for fluid oscillation modes of color superconducting self-bound stars

2012 ◽  
Vol 8 (S291) ◽  
pp. 451-451
Author(s):  
German Lugones ◽  
Cesar Vasquez Flores
Keyword(s):  
Equation Of State ◽  
Gravitational Waves ◽  
Internal Structure ◽  
Quark Matter ◽  
Normal Modes ◽  
Pressure Oscillation ◽  
Compact Stars ◽  
Color Superconductivity ◽  
Strange Stars ◽  
Oscillation Modes

AbstractThe investigation of the quasi-normal modes of oscillation of compact stars can reveal much information about their equation of state and internal structure mainly through the analysis of the expected emission of gravitational waves. In this work we study non-radial oscillation modes of strange stars consisting of color superconducting quark matter. We focus on the fundamental and pressure oscillation modes within the frame of the Cowling approximation. We discuss the observable features that may allow a differentiation among hadronic stars, strange stars, and strange stars with color superconductivity.

Quantum 20/20

2019 ◽  
Author(s):  
Ian R. Kenyon
Keyword(s):  
Quantum Mechanics ◽  
Hall Effect ◽  
Particle Physics ◽  
Quantum Spin ◽  
Lessons Learned ◽  
Compact Stars ◽  
Einstein Condensation ◽  
Local Conservation ◽  
Variable Theory ◽  
Quantum Gauge Theory

This text reviews fundametals and incorporates key themes of quantum physics. One theme contrasts boson condensation and fermion exclusivity. Bose–Einstein condensation is basic to superconductivity, superfluidity and gaseous BEC. Fermion exclusivity leads to compact stars and to atomic structure, and thence to the band structure of metals and semiconductors with applications in material science, modern optics and electronics. A second theme is that a wavefunction at a point, and in particular its phase is unique (ignoring a global phase change). If there are symmetries, conservation laws follow and quantum states which are eigenfunctions of the conserved quantities. By contrast with no particular symmetry topological effects occur such as the Bohm–Aharonov effect: also stable vortex formation in superfluids, superconductors and BEC, all these having quantized circulation of some sort. The quantum Hall effect and quantum spin Hall effect are ab initio topological. A third theme is entanglement: a feature that distinguishes the quantum world from the classical world. This property led Einstein, Podolsky and Rosen to the view that quantum mechanics is an incomplete physical theory. Bell proposed the way that any underlying local hidden variable theory could be, and was experimentally rejected. Powerful tools in quantum optics, including near-term secure communications, rely on entanglement. It was exploited in the the measurement of CP violation in the decay of beauty mesons. A fourth theme is the limitations on measurement precision set by quantum mechanics. These can be circumvented by quantum non-demolition techniques and by squeezing phase space so that the uncertainty is moved to a variable conjugate to that being measured. The boundaries of precision are explored in the measurement of g-2 for the electron, and in the detection of gravitational waves by LIGO; the latter achievement has opened a new window on the Universe. The fifth and last theme is quantum field theory. This is based on local conservation of charges. It reaches its most impressive form in the quantum gauge theories of the strong, electromagnetic and weak interactions, culminating in the discovery of the Higgs. Where particle physics has particles condensed matter has a galaxy of pseudoparticles that exist only in matter and are always in some sense special to particular states of matter. Emergent phenomena in matter are successfully modelled and analysed using quasiparticles and quantum theory. Lessons learned in that way on spontaneous symmetry breaking in superconductivity were the key to constructing a consistent quantum gauge theory of electroweak processes in particle physics.

A New Instability of Accretion Disks around Magnetic Compact Stars

1998 ◽  
Vol 503 (1) ◽  
pp. 350-360 ◽  
Author(s):  
Mario Vietri ◽  
Luigi Stella
Keyword(s):  
Accretion Disks ◽  
Compact Stars
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