Chameleon Mechanism in Inhomogeneous Astrophysical Objects. (arXiv:1909.02890v1 [gr-qc])
<a href="http://arxiv.org/find/gr-qc/1/au:+Largani_N/0/1/0/all/0/1">Noshad Khosravi Largani</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Mirtorabi_M/0/1/0/all/0/1">Mohammad Taghi Mirtorabi</a>
Observational evidence implying the accelerated expansion of the universe has
been the motivation to develop various classes of modified gravity theories.
One of them uses the so-called “screening mechanism”, which is successful in
reproducing the observed gravitational behavior in large scales as well as
being in agreement with tests of general relativity in the solar system. In
this work, we investigate an example of scalar-tensor theories with screening
mechanism, namely the profile of a Chameleon field around inhomogeneous
astrophysical objects. According to [Khoury and Weltman(2004)], one can define
two kinds of approaches applicable to the thin shell and thick shell regimes,
that allow for a solution to the Chameleon equation of motion. For sufficiently
large objects, the scalar field can be assumed to propagate from a thin shell
of the object instead of the whole body, which simplifies the problem. On the
other hand, this solution is not practical in small objects. We find that in
inhomogeneous objects this is not trivial and at least one more factor, which
turns out to be the density, can change the way of approaching this problem.
Observational evidence implying the accelerated expansion of the universe has
been the motivation to develop various classes of modified gravity theories.
One of them uses the so-called “screening mechanism”, which is successful in
reproducing the observed gravitational behavior in large scales as well as
being in agreement with tests of general relativity in the solar system. In
this work, we investigate an example of scalar-tensor theories with screening
mechanism, namely the profile of a Chameleon field around inhomogeneous
astrophysical objects. According to [Khoury and Weltman(2004)], one can define
two kinds of approaches applicable to the thin shell and thick shell regimes,
that allow for a solution to the Chameleon equation of motion. For sufficiently
large objects, the scalar field can be assumed to propagate from a thin shell
of the object instead of the whole body, which simplifies the problem. On the
other hand, this solution is not practical in small objects. We find that in
inhomogeneous objects this is not trivial and at least one more factor, which
turns out to be the density, can change the way of approaching this problem.
http://arxiv.org/icons/sfx.gif
