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Nawal H. Siddig

Publications and source records attributed to Nawal H. Siddig.

2 recordsLinked to original sources

Chiral Vortical Transport under Minimal-Length Deformations in Rotating Relativistic Matter

We study how a minimal length can affect the chiral vortical effect, in which rotation produces a current in matter made of chiral fermions. We focus on an isotropic modification of the momentum-space density-of-state (DoS) and determine the vortical conductivity from the static, long-wavelength correlation between the current and momentum density. The analysis is carried out first for a single right-handed Weyl fermion and is then extended to general massless chiral fermion systems with mutually commuting conserved charges. We find that, for a broad class of analytic isotropic DoS modifications, the familiar leading contributions from chemical potential and temperature remain unchanged at first order within the DoS sector. Minimal-length effects instead appear through higher-order thermal and chemical-potential contributions. Some of these corrections contain the same chiral charge combinations that appear in gauge and mixed gauge-gravitational anomalies, while another contains an independent higher-order charge combination. Their coefficients depend on the form of the DoS modification and are therefore not fixed by the usual four-dimensional anomaly structure. For the Kempf-Mangano-Mann deformation, the exact result shows that a positive minimal-length parameter always reduces the DoS contribution to the vortical conductivity. We also find that a Planck-suppressed correction is extremely small under standard heavy-ion chemical freeze-out conditions. These results show that isotropic minimal-length modifications can change higher-order contributions to chiral vortical transport while leaving the familiar leading anomaly-related response unchanged within the DoS sector considered here.

hep-ph↗

Properties of strange quark stars in $f(Q)$ gravity: A baryon number density-dependent perspective

We study anisotropic strange quark stars in $f(Q)$ gravity, incorporating a baryon-number-density-dependent bag function $B(n)$ into the MIT bag equation of state, $p=[ρ-4B(n)]/3$. Motivated by a Woods-Saxon parametrization, the density dependence of $B(n)$ provides a phenomenological description of the evolution of quark matter with increasing baryon density beyond the conventional constant-bag prescription. Adopting the Finch-Skea metric ansatz, we obtain exact solutions of the modified field equations for anisotropic matter composed of deconfined up, down and strange quarks. We investigate the thermodynamic stability through the energy per baryon, $E_B=ρ_0/n$, as a function of baryon density and identify the regimes corresponding to stable hadronic matter, metastable hybrid matter and absolutely stable strange quark matter. At sufficiently high densities, $E_B$ falls below the corresponding value for $^{56}$Fe, satisfying the stability criterion for strange quark matter. The resulting stability window, $57.55\leq B(n)\leq 91.55~\mathrm{MeV/fm^3}$, supports stable three-flavour quark matter. Solving the generalized Tolman-Oppenheimer-Volkoff equations, we find a maximum stellar mass of $\sim2.46,M_\odot$, demonstrating that the model can accommodate massive compact stars. The resulting configurations satisfy the relevant causality and energy condition constraints, while their stability is supported by the Herrera cracking criterion and the adiabatic index. These results demonstrate that the combined effects of nonmetricity and a density-dependent bag function can substantially enrich the phenomenology of strange quark stars and provide a viable framework for exploring their internal structure and stability in modified gravity.

gr-qc↗