相关论文: Screening Solutions in Modified Gravity Theories
A specific value for the cosmological constant, \Lambda, can account for late-time cosmic acceleration. However, motivated by the so-called cosmological constant problem(s), several alternative mechanisms have been explored. To date, a host…
Viable modifications of gravity on cosmological scales predominantly rely on screening mechanisms to recover Einstein's Theory of General Relativity in the Solar System, where it has been well tested. A parametrisation of the effects of…
In this paper, we revisit the solar system tests of f(R) gravity. When the Sun sits in a vacuum, the field f' is light, which leads to a metric different from the observations. We reobtain this result in a simpler way by directly focusing…
In previous work it was shown that MOND theories predict anomalously strong tidal stresses near the saddle points of the Newtonian gravitational potential. An analytical examination of the saddle between two bodies revealed a linear and a…
This thesis introduces a set of methods for testing models of modified gravity using galaxy clusters. In particular, a technique for constraining models with a chameleon screening is introduced. In addition, the outlined technique is…
The non-linear dynamics of scalar fields coupled to matter and gravity can lead to remarkable density-dependent screening effects. In this short review we present the main classes of screening mechanisms, and discuss their tests in…
Modifications of gravity have been considered to model the primordial inflation and the late-time cosmic acceleration. Provided that modified gravity models do not suffer from theoretical instabilities, they must be confronted with…
Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the universe. We review recent developments in modified gravity theories, focusing on higher dimensional approaches and…
We consider the possibility of the detection of a chameleon effect by an earth orbiting satellite such as LAGEOS, and possible constraints that might be placed on chameleon model parameters. Approximate constraints presented here result…
We describe and demonstrate the potential of a new and very efficient method for simulating certain classes of modified gravity theories, such as the widely studied $f(R)$ gravity models. High resolution simulations for such models are…
Building on previous work, we explore the parameter space of free functions in non-relativistic modified gravity theories more widely, showing that in fact the two broad regimes present have similar functional forms between different…
A feasible design for a magnetic diagnostics subsystem for eLISA will be based on that of its precursor mission, LISA Pathfinder. Previous experience indicates that magnetic field estimation at the positions of the test masses has certain…
The radiation pressure due to reflected chameleons is suggested for their detection. Sensitive photon radiation pressure or force measuring techniques could become the new antennas for chameleons or other particles with similar properties,…
Recently, a model $f(R)$ theory is proposed \cite{recent} which is cosmologically viable and distinguishable from $\Lambda$CDM. We use chameleon mechanism to investigate viability of the model in terms of Solar System experiments.
Screened modified gravity predicts potentially large signatures in the peculiar velocity field that makes it an interesting probe to test gravity on cosmological scales. We investigate the signatures induced by the Symmetron and a Chameleon…
We offer predictions of symmetron modified gravity in the neighborhood of realistic dark matter halos. The predictions for the fifth force are obtained by solving the nonlinear symmetron equation of motion in the spherical NFW…
Modified gravity theories may provide an alternative to dark energy to explain cosmic acceleration. We argue that the observational program developed to test dark energy needs to be augmented to capture new tests of gravity on astrophysical…
Models of modified gravity introduce extra degrees of freedom, which for consistency with the data, should be suppressed at observable scales. In the models that share properties of massive gravity such a suppression is due to nonlinear…
We constrain the Chameleon \textit{screening} mechanism in galaxy clusters, essentially obtaining limits on the coupling strength $\beta$ and the asymptotic value of the field $\phi_{\infty}$. For this purpose, we utilized a collection of…
We consider modified gravity models driven by a scalar field whose effects are screened in high density regions due to the presence of non-linearities in its interaction potential and/or its coupling to matter. Our approach covers…