arXiv subjects

Xing-Hua Jin

Publications and source records attributed to Xing-Hua Jin.

3 recordsLinked to original sources

arXiv2020

Strong gravitational lensing of a 4-dimensional Einstein-Gauss-Bonnet black hole in homogeneous plasma

We investigate the strong gravitational lensing of spherically symmetric black holes in the novel Einstein-Gauss-Bonnet(EGB) gravity surrounded by unmagnetised plasma medium. The deflection angle in the strong deflection limit in EGB spacetime with homogeneous plasma is derived. We find that both the coupling constant $α$ in the novel EGB gravity and the presence of plasma can affect the radius of photon sphere, strong field limit coefficient and other lensing observables significantly. While plasma has little effect on the angular image separation and the relative magnifications as $α/M^2\to -8$ and $α/M^2\to 1$, respectively.

gr-qc↗

arXiv2011

A modified model of non-locally corrected gravity: Cosmology and the Newtonian limit

A modified form of non-locally corrected theory of gravity is investigated in the context of cosmology and the Newtonian limit. This form of non-local correction to classic Einstein-Hilbert action can be locally represented by a triple-scalar-tensor theory in which one of the scalar degree of freedom is phantom-like and the other two are quintessence-like. We show that there exists a stable de Sitter solution for the cosmological dynamics if a suitable form of potential function $V(ϕ)$ (or equivalently, $f(R)$) is selected. However, no matter what a potential function is selected, there is always an early time repeller solution corresponding to a radiation dominated universe. Besides, the equations for linear scalar perturbations are presented and it is shown that the form of potential function $V(ϕ)$ is stringently constrained by the Solar system test, although the post-Newtonian parameter $γ$ is not directly affected by this function.

gr-qc↗

arXiv2008

Revisiting the parametrization of Equation of State of Dark Energy via SNIa Data

In this paper, we revisit the parameterizations of the equation of state of dark energy and point out that comparing merely the $χ^2$ of different fittings may not be optimal for choosing the "best" parametrization. Another figure of merit for evaluating different parametrizations based on the area of the $w(z) - z$ band is proposed. In light of the analysis of some two-parameter parameterizations and models based on available SNIa data, the area of $w(z)-z$ band seems to be a good figure of merit, especially in the situation that the value of $χ^2_{\rm min}$ for different parametrizations are very close. Therefore, we argue that both the area of the $w(z)-z$ band and $χ^2_{\rm min}$ should be synthetically considered for choosing a better parametrization of dark energy in the future experiments.

astro-ph↗