Zero sound in neutron stars with dense quark matter under strong magnetic fields

Kouvaris, Chris

doi:10.1103/physrevd.79.123008

Cited by 3 publications

(2 citation statements)

References 24 publications

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“…Collective modes in quantum many-body systems have received much attention because of observation of many-body quantum statistical nature, not only in superfluid states [1][2][3][4][5][6][7] but also in normal states [5,8,9]. In a Fermi system, collective modes in two regimes-the collisionless regime and the hydrodynamic regime-have been a central issue in liquid helium 3 He [10,11], neutron stars [12,13] as well as quantum gases [2,3,5,14]. In particular, the zero sound-the in-phase (density) sound mode in a collisionless regime-and the first sound-the density sound mode in a hydrodynamic regimehave been intensively and extensively investigated in twocomponent simple normal Fermi systems [10,12,[15][16][17][18], dipolar Fermi gases [19], polarized Fermi-liquid films [20], as well as Fermi gases with arbitrary spin [21].…”

Section: Introductionmentioning

confidence: 99%

Density and spin modes in imbalanced normal Fermi gases from collisionless to hydrodynamic regime

Narushima

Watabe

Nikuni

2018

J. Phys. B: At. Mol. Opt. Phys.

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We study mass and population imbalance effect on density (in-phase) and spin (out-of-phase) collective modes in a two-component normal Fermi gas. By calculating eigenmodes of the linearized Boltzmann equation as well as the density/spin dynamic structure factor, we show that mass and population imbalance effects offer a variety of collective mode crossover behaviors from collisionless to hydrodynamic regimes. The mass imbalance effect shifts the crossover regime to the higher-temperature, and a significant peak of the spin dynamic structure factor emerges only in the collisionless regime. This is in contrast to the case of mass and population balanced normal Fermi gases, where the spin dynamic response is always absent. Although the population imbalance effect does not shift the crossover regime, the spin dynamic structure factor survives both in the collisionless and hydrodynamic regimes.

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Section: Introductionmentioning

confidence: 99%

Density and spin modes in imbalanced normal Fermi gases from collisionless to hydrodynamic regime

Narushima

Watabe

Nikuni

2018

J. Phys. B: At. Mol. Opt. Phys.

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“…Their early cooling behavior is dominated by neutrino emission which is a useful probe of the internal composition of compact stars. Thus, cooling simulations provide an effective test of the nature of compact stars [6][7][8][9][10][11][12][13][14][15][16]. However, many theoretical uncertainties and the current amount of data on the surface temperatures of neutron stars leave sufficient room for speculations [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic hydrodynamics, bulk viscosities, andr-modes of strange quark stars with strong magnetic fields

et al. 2010

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In strong magnetic fields the transport coefficients of strange quark matter become anisotropic. We determine the general form of the complete set of transport coefficients in the presence of a strong magnetic field. By using a local linear response method, we calculate explicitly the bulk viscosities ζ ⊥ and ζ transverse and parallel to the B-field respectively, which arise due to the non-leptonic weak processes u + s ↔ u + d. We find that for magnetic fields B < 10 17 G, the dependence of ζ ⊥ and ζ on the field is weak, and they can be approximated by the bulk viscosity for zero magnetic field. For fields B > 10 18 G, the dependence of both ζ ⊥ and ζ on the field is strong, and they exhibit de Haas-van Alphen-type oscillations. With increasing magnetic field, the amplitude of these oscillations increases, which eventually leads to negative ζ ⊥ in some regions of parameter space. We show that the change of sign of ζ ⊥ signals a hydrodynamic instability. As an application, we discuss the effects of the new bulk viscosities on the r-mode instability in rotating strange quark stars. We find that the instability region in strange quark stars is affected when the magnetic fields exceeds the value B = 10 17 G. For fields which are larger by an order of magnitude, the instability region is significantly enlarged, making magnetized strange stars more susceptible to r-mode instability than their unmagnetized counterparts.

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Anisotropy in the equation of state of magnetized quark matter

2015

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The anisotropies in the pressure obtained from the energy-momentum tensor are studied for magnetized quark matter within the su(3) Nambu-Jona-Lasinio model for both β-equilibrium matter and quark matter with equal quark chemical potentials. The effect of the magnetic field on the particle polarization, magnetization, and quark matter constituents is discussed. It is shown that the onset of the s quark after chiral symmetry restoration of the u and d quarks gives rise to a special effect on the magnetization in the corresponding density range: A quite small magnetization just before the s onset is followed by a strong increase of this quantity as soon as the s quark sets in. It is also demonstrated that for B < 10 18 G within the two scenarios discussed, always considering a constant magnetic field, the two components of pressure are practically coincident. The structure of the QCD phase diagram is of utmost importance in understanding many physical aspects of nature, ranging from the early universe to possible nuclear liquid-gas and hadronic quark matter phase transitions to the physics of compact objects [1]. Early analyzes performed within the Nambu-Jona-Lasinio model (NJL) framework indicate that when strongly interacting matter is subject to intense magnetic fields the QCD phase diagram boundaries are modified [2]. Some of the most important changes concern the size and location of the first-order chiral transition region since the results show that a strong magnetic field favors this type of transition. At the same time, at low temperatures, the value of the coexistence chemical potential decreases as B increases in accordance with the inverse magnetic catalysis (ICM) phenomenon [3].The low-T and high-μ region where a first-order-type transition is expected to occur is currently unavailable to lattice QCD evaluations (LQCD). However, the region high-T and low-μ has already been exploited using LQCD simulations which indicate, in accordance with most model predictions, that the crossover observed at B = 0 persists when B = 0 [4][5][6][7]. On the other hand, a major disagreement between recent LQCD results [6,7] and model calculations regards the dependence of crossover pseudocritical temperature, T pc , on the strength B of the magnetic field. Specifically, the lattice results of Refs. [6,7], performed with 2 + 1 quark flavors and physical pion mass values, predict an inverse catalysis, with T pc decreasing with B, while effective models predict an increase of T pc with B. This problem has been recently addressed by different groups [8,9], who basically agree that the different results stem from the fact that most effective models miss back reaction effects (the indirect interaction of gluons and B) as well as the QCD asymptotic freedom phenomenon. At the same time, other important aspects of the effects of strong magnetic fields on the QCD phase diagram have already been studied, including the behavior of the coexistence chemical potential and the location of the critical end point (CEP) [10], the dependenc...

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Zero sound in neutron stars with dense quark matter under strong magnetic fields

Cited by 3 publications

References 24 publications

Density and spin modes in imbalanced normal Fermi gases from collisionless to hydrodynamic regime

Density and spin modes in imbalanced normal Fermi gases from collisionless to hydrodynamic regime

Anisotropic hydrodynamics, bulk viscosities, andr-modes of strange quark stars with strong magnetic fields

Anisotropy in the equation of state of magnetized quark matter

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