Magnetized Strange Quark Matter Research Articles

Magnetized Strange Quark Models in Lyra Theory

In this study, the behavior of magnetized strange quark matter (MSQM) distribution in Lyra theory was investigated for homogeneous anisotropic Bianchi III, locally rotationally symmetric (LRS) Bianchi I, and Kantowski-Sachs universe models. We have used the equations of state, anisotropy, and linearly varying deceleration parameters to obtain the exact solutions of field equations in Lyra theory. When switching from the anisotropic universe model to the isotropic universe model, the magnetic field was not observed in the LRS Bianchi I universe. Besides, the graphs of the dynamic quantities obtained for each universe model were analyzed in detail. Finally, we inquire whether further research should be conducted.

Does magnetized strange quark matter exist in the early universe?

In this paper, we have examined the magnetized strange quark matter (MSQM) distribution in the inhomogeneous anisotropic Einstein–Rosen universe model within the framework of [Formula: see text] theory and General Relativity (GR) in order to investigate whether there was a magnetic field in the first moments of the universe. With the help of the arbitrary [Formula: see text] function, we researched for solutions in both theories for various cases. We have seen that the cubic function [Formula: see text] gives meaningful results in both theories. We have obtained magnetic field-free strange quark matter solutions for the quadratic and constant states of the arbitrary function [Formula: see text]. It is seen that the choice of geometry (selection of the [Formula: see text] function) has an effect on the presence of the magnetic field. Finally, the physical results are examined on 3D graph.

Behaviour of Magnetized Strange Quark Matter in f(R,T) Theory for General Kantowski-Sachs Model

In this study, we have investigated the behavior of magnetized strange quark matter (MSQM) in f(R,T) gravity for LRS Bianchi I, Bianchi III and Kantowski-Sachs (GKS) universe models with cosmological term. For the solutions of modified field equations, we have used linearly varying deceleration parameter (LVDP), anisotropy parameter and equation of state for strange quark matter. When the models goes to the isotropy magnetic field only occurs in Bianchi III and Kantowski-Sachs universe models. When t→∞, strange quark matter distribution behaves like dark energy. The K(θ) parameter, which allows us to obtain different universe models, is effective on the magnetic field, cosmological term and f(R,T) function. In addition, the graphics of the obtained results were examined in detail.

Effect of vector interaction on magnetized strange quark matter and strange quark star

This study investigates the thermodynamical properties of magnetized strange quark matter (MSQM) and magnetized strange quark stars (MSQSs), the longitudinal and transverse equation of state (EoS), the maximum mass, the love number, tidal deformability, and gravitational redshift for MSQSs in chiral SU(3) quark mean-field (CQMF) model. The effects of vector interactions and density-dependent magnetic field are considered in the calculations. The EoS having longitudinal pressure gets soften with an increase in magnetic field and becomes stiffer for transverse pressure. The derived results show that the maximum mass of SQSs depends not only on the strength of the magnetic field but also on the orientation of the magnetic field inside the stars. The maximum mass and tidal deformability of MSQSs show good agreement with both the constraints of PSR J0030+0451 measured by NICER and the tidal deformability of gravitational wave event (GW170817) observed by LIGO and Virgo collaboration. In addition, the structure of MSQS is investigated using an axially symmetric metric with spherical coordinates in which γ- parameter observes the deformation of the star due to magnetic field.

Bulk viscosity of interacting magnetized strange quark matter

Bulk viscosity of interacting magnetized strange quark matter

Magnetized strange quark model with cosmological term in modified gravity of anisotropic cosmology

We study the Magnetized Strange Quark Matter (MSQM) solutions for Bianchi type-I universe in the two models of modified gravity f(R,T) in presence of variable cosmological term Λ=Λ(t). The models are characterized by the functions of the forms f(R,T)=(R+2μTandμ(R+T)) based on the plausible relations. The results indicate that, although the magnetic flux (as a byproduct of the models) does not appear, the models can exhibit de-Sitter like manifestations or situations resembling the cosmological standard model in the early or late times of the universe evolution. Some physical aspects of models are also discussed.

Anisotropic universe models with magnetized strange quark matter in f(R) gravity theory

In this study, we have investigated generalized anisotropic universe models for magnetized strange quark matter (MSQM) distribution in the framework of [Formula: see text] gravitation theory. For this aim, we have used linearly varying deceleration parameter suggested by Akarsu and Dereli (2012) and equation of state for strange quark matter. For LRS Bianchi I universe model, the magnetic field was obtained as zero. But it was found to be different from zero for other universe models. Also, the geometric and physical aspects of the model are discussed in the conclusion.

Chiral symmetry breaking, color superconductivity, and equation of state for magnetized strange quark matter

We investigate the vacuum structure of dense quark matter in strong magnetic fields at finite temperature and densities in a 3 flavor Nambu Jona Lasinio (NJL) model including the Kobayashi-Maskawa-t'Hooft (KMT) determinant term using a variational method. The method uses an explicit structure for the `ground' state in terms of quark-antiquark condensates as well as diquark condensates. The mass gap equations and the superconducting gap equations are solved self consistently and are used to compute the thermodynamic potential along with the charge neutrality conditions. We also derive the equation of state for the charge neutral strange quark matter in the presence of strong magnetic fields which could be relevant for neutron stars.

Anisotropic pressure in strange quark matter in the presence of a strong nonuniform magnetic field

Thermodynamic properties of strange quark matter (SQM) in a nonuniform magnetic field are studied within the phenomenological MIT bag model under the charge neutrality and beta equilibrium conditions, relevant to the interior of strange quark stars. The spatial dependence of the magnetic field strength is modeled by the dependence on the baryon chemical potential in the exponential and power forms. The total energy density, longitudinal and transverse pressures in magnetized SQM are found as functions of the baryon chemical potential. It is clarified that the central magnetic field strength in a strange quark star is bound from above by the critical value at which the derivative of the longitudinal pressure with respect to the baryon chemical potential vanishes first somewhere in the interior of a star under varying the central field. Above this upper bound, the instability along the magnetic field is developed in magnetized SQM. The change in the form of the dependence of the magnetic field strength on the baryon chemical potential between the exponential and power ones has a nonnegligible effect on the critical magnetic field strength while the variation of the bag pressure within the absolute stability window for magnetized SQM has a little effect on the critical field.

Relationship between magnetic field and anisotropy parameter in gravitation theories

The magnetized strange quark matter (MSQM) solutions are obtained for a Marder type universe using constant deceleration parameter. The exact solutions of field equations are obtained for f(R,[Formula: see text]T) = R + 2f(T) model given by [T. Harko et al., Phys. Rev. D 84, 024020 (2011)] with cosmological term. Also, we have obtained General Relativity (GR) solutions for MSQM distributions. For [Formula: see text], we get the dark energy model, i.e. [Formula: see text], [Formula: see text] and [Formula: see text]. However, for [Formula: see text], we find the cosmological constant [Formula: see text] as negative in f(R,[Formula: see text]T) theory and GR. These results agree with [S. Aygün et al., Astrophys. Space Sci. 361, 380 (2016); C. Aktaş and S. Aygün, Chinese J. Phys. 55, 71 (2017); P. K. Sahoo et al., Mod. Phys. Lett. A 32, 1750105 (2017)] in f(R,[Formula: see text]T) theory. The physical consequences of our obtained models are discussed at the end.

Magnetized strange quark matter in f(R, T) gravity with bilinear and special form of time varying deceleration parameter

In this paper, we have studied homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi type-I model with magnetized strange quark matter (MSQM) distribution and cosmological constant Λ in f(R, T) gravity where R is the Ricci scalar and T the trace of matter source. The exact solutions of the field equations are obtained under bilinear and special form of time varying deceleration parameter (DP). Firstly, we have considered two specific forms of bilinear DP with a single parameter of the form: q=α(1−t)1+t and q=−αt1+t, which leads to the constant or linear nature of the function based on the constant α. Second one is the special form of the DP as q=−1+β1+aβ. From the results obtained here, one can observe that in the early universe magnetic flux has more effects and it reduces gradually in the later stage. For t → ∞, we get p→−Bc and ρ → Bc. The behaviour of strange quark matter along with magnetic epoch gives an idea of accelerated expansion of the universe as per the observations of the type Ia Supernovae.

Anisotropic structure equations in magnetized quark stars

AbstractIt is well‐known that a magnetic field in a fermion system breaks the SO(3) symmetry, giving rise to an anisotropy in the energy‐momentum tensor and consequently in the equation of state (EoS). Thus, the stellar structure equations of magnetized quark stars (QS) demand to be derived from a more appropriate cylindrical metric. In this work we obtain these equations considering the magnetized quark matter in two phases: Magnetized Strange Quark Matter (MSQM) and Magnetized Color Flavor Locked Phase (MCFL). The main outcome of our work is the value of the maximum magnetic field that an star can hold, i.e. 1018 G. This upper bound is closely related to the violation of the virial relations and also with the instability associated with parity‐violation weak processes during the collapse of supernovae. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Anisotropic pressure in the quark core of a strongly magnetized hybrid star

The impact of a strong magnetic field, varying with the total baryon number density, on thermodynamic properties of strange quark matter (SQM) in the core of a magnetized hybrid star is considered at zero temperature within the framework of the Massachusetts Institute of Technology (MIT) bag model. It is clarified that the central magnetic field strength is bound from above by the value at which the derivative of the longitudinal pressure with respect to the baryon number density vanishes first somewhere in the quark core under varying the central field. Above this upper bound, the instability along the magnetic field is developed in magnetized SQM. The total energy density, longitudinal and transverse pressures are found as functions of the total baryon number density.

Stability of magnetized strange quark matter in the MIT bag model with a density dependent bag pressure

The stability of magnetized strange quark matter (MSQM) is studied in the MIT bag model with the density dependent bag pressure. In the consistent thermodynamic description of MSQM, the quark chemical potentials, the total thermodynamic potential and the anisotropic pressure acquire the corresponding additional term proportional to the density derivative of the bag pressure. The model parameter space is determined, for which MSQM is absolutely stable, i.e., its energy per baryon is less than that of the most stable $^{56}$Fe nucleus under the zero external pressure and vanishing temperature. It is shown that there exists the magnetic field strength $H_{u\,max}$ at which the upper bound $B_\infty^u$ on the asymptotic bag pressure $B_\infty\equiv B(\varrho_B\gg \varrho_0$) ($\varrho_0$ being the nuclear saturation density) from the absolute stability window vanishes. The value of this field, \hbox{$H_{u\,max}\sim$$(1$--$3)\cdot10^{18}$}~G, represents the upper bound on the magnetic field strength, which can be reached in a strongly magnetized strange quark star. It is clarified how the absolute stability window and upper bound on the magnetic field strength are affected by varying the parameters in the Gaussian parametrization for the density dependence of the bag pressure.

Magnetized strange quark matter in a mass-density-dependent model

We investigate the properties of strange quark matter (SQM) in a strong magnetic field with quark confinement by the density dependence of quark masses considering the total baryon number conservation, charge neutrality and chemical equilibrium. It is found that an additional term should appear in the pressure expression to maintain thermodynamic consistency. At fixed density, the energy density of magnetized SQM varies with the magnetic field strength. By increasing the field strength an energy minimum exists located at about 6×1019 Gauss when the density is fixed at two times the normal nuclear saturation density.

Absolute stability window and upper bound on the magnetic field strength in a strongly magnetized strange quark star

Magnetized strange quark stars, composed of strange quark matter (SQM) and self-bound by strong interactions, can be formed if the energy per baryon of magnetized SQM is less than that of the most stable 56Fe nucleus under the zero external pressure and temperature. Utilizing the MIT bag model description of magnetized SQM under charge neutrality and beta equilibrium conditions, the corresponding absolute stability window in the parameter space of the theory is determined. It is shown that there exists the maximum magnetic field strength allowed by the condition of absolute stability of magnetized SQM. The value of this field, H ~ 3 × 1018 G , represents the upper bound on the magnetic field strength which can be reached in a strongly magnetized strange quark star.

Strange Quark Matter and Strangelets in a Strong Magnetic Field

We study the stability properties of magnetized strange quark matter and strangelets under a strong magnetic field in the MIT bag model. The free energy per baryon of strange quark matter feels a great influence from the magnetic held. At the held strength about 1017 G, the magnetized strange quark matter becomes more stable. Considering the finite size effect, the magnetic influence on strangelets becomes complicated. For a given magnetic held, there exists a critical baryon number, below which the magnetized strangelets have lower energy than the non-magnetized strangelets. For the held strength of 5 × 1017 G, the critical baryon number is Ac ∼ 100. Generally, the critical baryon number increases with the decreasing external magnetic held. When the held strength is smaller than 1017 G, the critical baryon number goes up to Ac ∼ 105. The stable radius, electric charge, and quark flavor fractions of magnetized strangelets are shown.

Upper bound on the magnetic field strength in the quark core of a strongly-magnetized compact star

Two types of strongly-magnetized compact stars, represented by magnetized strange quark stars and magnetized hybrid stars, are considered. In each case, there exists an upper bound H max on the magnetic field strength in the interior of a compact star. For a magnetized strange quark star, H max is determined by the magnetic field at which the upper bound on the bag pressure from the absolute stability window of magnetized strange quark matter (SQM) vanishes, assuming the Massachusetts Institute of Technology bag model description of SQM. For a hybrid star, H max is represented by the critical magnetic field for the occurrence of a longitudinal (along the magnetic field) instability in the quark core, at which the longitudinal pressure in magnetized SQM vanishes.

Magnetized strangelets at finite temperature

The main properties of strangelets, namely their energy per baryon, radius and electric charge, are studied in the unpaired magnetized strange quark matter (MSQM) and paired magnetized colour flavour locked (MCFL) phases. Temperature effects are taken into account in order to study their stability compared to the 56Fe isotope and nonmagnetized strangelets within the framework of the MIT bag model. We conclude that the presence of a magnetic field tends to stabilize the strangelets more, even when temperature is considered. It is also shown that MCFL strangelets are more stable than ordinary MSQM strangelets for typical gap values of the order of MeV. A distinctive feature in the detection of strangelets either in cosmic rays or in heavy-ion collider experiments could be their electric charge. We find that the electric charge is modified in the presence of the magnetic field, leading to higher (lower) charge values for MSQM (MCFL) strangelets, when compared to the nonmagnetized case.

COMPACT STARS AND MAGNETIZED CFL MATTER

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.