f(R)f(R) gravity theories in the Palatini Formalism constrained from strong lensing

$f(R)$ gravity, capable of driving the late-time acceleration of the universe, is emerging as a promising alternative to dark energy. Various $f(R)$ gravity models have been intensively tested against probes of the expansion history, including type Ia supernovae (SNIa), the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO). In this paper we propose to use the statistical lens sample from Sloan Digital Sky Survey Quasar Lens Search Data Release 3 (SQLS DR3) to constrain $f(R)$ gravity models. This sample can probe the expansion history up to $z\sim2.2$, higher than what probed by current SNIa and BAO data. We adopt a typical parameterization of the form $f(R)=R-\alpha H^2_0(-\frac{R}{H^2_0})^\beta$ with $\alpha$ and $\beta$ constants. For $\beta=0$ ($\Lambda$CDM), we obtain the best-fit value of the parameter $\alpha=-4.193$, for which the 95% confidence interval that is [-4.633, -3.754]. This best-fit value of $\alpha$ corresponds to the matter density parameter $\Omega_{m0}=0.301$, consistent with constraints from other probes. Allowing $\beta$ to be free, the best-fit parameters are $(\alpha, \beta)=(-3.777, 0.06195)$. Consequently, we give $\Omega_{m0}=0.285$ and the deceleration parameter $q_0=-0.544$. At the 95% confidence level, $\alpha$ and $\beta$ are constrained to [-4.67, -2.89] and [-0.078, 0.202] respectively. Clearly, given the currently limited sample size, we can only constrain $\beta$ within the accuracy of $\Delta\beta\sim 0.1$ and thus can not distinguish between $\Lambda$CDM and $f(R)$ gravity with high significance, and actually, the former lies in the 68% confidence contour. We expect that the extension of the SQLS DR3 lens sample to the SDSS DR5 and SDSS-II will make constraints on the model more stringent.Comment: 10 pages, 7 figures. Accepted for publication in MNRA

¿Qué puede hacer China para desarrollar en una mayor medida el Derecho Penal Internacional y la Justicia desde la perspectiva del Tribunal Penal Internacional?

The Rome Statute, as well as the International Criminal Court (ICC), regarded as a worldwide mechanism for the fight for impunity and a better protection of human rights, has 124 State parties up to date. China, however, is still not a party to the Rome Statute, mainly because of five reasons. This article looks for promoting the academic research on the Rome Statute and the ICC to clarify some confusion, and strengthening the Chinese domestic legislation to make use of the principle of complementary jurisdiction to exclude the jurisdiction of the ICC at largest. It is possible for China to be ready to access to the Rome Statute and take part in the ICC club in the future, which is also a contribution of China to the development of the international criminal law and justice.El Estatuto de Roma, así como el Tribunal Penal Internacional (TPI), considerado como un mecanismo mundial para la lucha contra la impunidad y una mejor protección de los derechos humanos, tiene actualmente 124 Estados partes. China, sin embargo, todavía no es parte del Estatuto de Roma, debido principalmente a cinco motivos.Este artículo busca promover la investigación académica sobre el Estatuto de Roma y el TPI, para aclarar cierta confusión, y para fortalecer la legislación nacional de China a fin de hacer uso del principio de jurisdicción complementaria a fin de restringir la jurisdicción del TPI. Es posible queChina esté lista para unirse en un futuro próximo al Estatuto de Roma y participar en el TPI, lo cual sería también una contribución de China en el desarrollo del derecho penal internacional y la justicia