arXiv subjects

Hao-Yu Qi

Publications and source records attributed to Hao-Yu Qi.

2 recordsLinked to original sources

arXiv2012

Constraining $f(T)$ Theories with the Varying Gravitational Constant

As is well known, a varying effective gravitational "constant" is one of the common features of most modified gravity theories. Of course, as a modified gravity theory, $f(T)$ theory is not an exception. Noting that the observational constraint on the varying gravitational "constant" is very tight, in the present work we try to constrain $f(T)$ theories with the varying gravitational "constant". We find that the allowed model parameter $n$ or $β$ has been significantly shrunk to a very narrow range around zero. In fact, the results improve the previous constraints by an order of magnitude.

gr-qc↗

arXiv2011

$f(T)$ Theories and Varying Fine Structure Constant

In analogy to $f(R)$ theory, recently a new modified gravity theory, namely the so-called $f(T)$ theory, has been proposed to drive the current accelerated expansion without invoking dark energy. In the present work, by extending Bisabr's idea, we try to constrain $f(T)$ theories with the varying fine structure "constant", $α\equiv e^2/\hbar c$. We find that the constraints on $f(T)$ theories from the observational $Δα/α$ data are very severe. In fact, they make $f(T)$ theories almost indistinguishable from $Λ$CDM model.

gr-qc↗