Related papers: Chameleon Dark Energy and Atom Interferometry
Dark energy models with a single scalar field cannot cross the equation of state divide set by a cosmological constant. More general models that allow crossing require additional degrees of freedom to ensure gravitational stability. We show…
While considering the chameleon scalar field model with the spatially flat FLRW background, we investigate the late-time acceleration phase of the universe, wherein we apply the typical potential usually used in this model. Through setting…
Understanding the nature of dark energy and dark matter is one of modern physics' greatest open problems. Scalar-tensor theories with screened scalar fields like the chameleon model are among the most popular proposed solutions. In this…
In the chameleon mechanism, a field (typically scalar) has a mass that depends on the matter density of the environment: the larger is the matter density, the larger is the mass of the chameleon. We briefly review some aspects of…
f(R) gravity is one of the simplest generalizations of general relativity, which may explain the accelerated cosmic expansion without introducing a cosmological constant. Transformed into the Einstein frame, a new scalar degree of freedom…
We study general properties of attractors for tachyonic potential chameleon scalar-field model which possess cosmological scaling solutions. An analytic formulation is given to obtain fixed points with a discussion on their stability. The…
The mass of a scalar field mediating a fifth force is tightly constrained by experiments. We show, however, that adding a quartic self-interaction for such a scalar makes most tests much less constraining: the non-linear equation of motion…
This paper describes the concept and the beginning of an experimental investigation of whether it is possible to directly detect dark energy density on earth using atom interferometry. The concept is to null out the gravitational force…
We study the quantum force between classical objects mediated by massive scalar fields bilinearly coupled to matter. The existence of such fields is motivated by dark matter, dark energy, and by the possibility of a hidden sector beyond the…
We perform high resolution N-body simulations for f(R) gravity based on a self-adaptive particle- mesh code MLAPM. The Chameleon mechanism that recovers General Relativity on small scales is fully taken into account by self-consistently…
We consider the Post-Newtonian limit of massive Brans-Dicke theory and we make some notes about the Post-Newtonian limit of the case $\omega=0$. This case is dynamically equivalent to the metric $f(R)$ theory. It is known that this theory…
The symmetron is a typical example of screened modified gravity, wherein the symmetron force is dynamically suppressed in dense environments. This allows it to hide in traditional tests of gravity. However, the past decade has seen great…
Chameleon and similar (symmetron and dilation) theories of gravity can exhibit new and interesting features on cosmological scales whilst screening the modifications on small scales thereby satisfying solar system tests of general…
The use of machine learning to estimate the energy of a group of atoms, and the forces that drive them to more stable configurations, has revolutionized the fields of computational chemistry and materials discovery. In this domain, rigorous…
Cosmological models exhibiting crossing of the phantom divide improve the fit to current data, suggesting late-time dark energy (DE) dynamics at $\sim3\sigma$ CL. However, they favor low values of $H_0$, in tension with SH0ES. This may…
We investigate the effects of chameleon scalar field to the effective density and pressure of a dark matter halo. The pressure is generated from the chameleonic fifth force on the matter. We demonstrate that the thick-shell non-singular…
Additional scalar fields from scalar-tensor, modified gravity or higher dimensional theories beyond general relativity may account for dark energy and the accelerating expansion of the Universe. These theories have lead to proposed models…
We investigate the behavior of the fifth force in voids in chameleon models using the spherical collapse method. Contrary to Newtonian gravity, we find the fifth force is repulsive in voids. The strength of the fifth force depends on the…
In this article we discuss some aspects of solar physics from the standpoint of the so-called chameleon fields (i.e. quantum fields, typically scalar, where the mass is an increasing function of the matter density of the environment).…
Chameleons are scalar fields that couple directly to ordinary matter with gravitational strength, but which nevertheless evade the stringent constraints on tests of gravity because of properties they acquire in the presence of high ambient…