Related papers: Testing Chameleons Using Neutron Interferometry
The late-time accelerated expansion of the universe could be caused by a scalar field that is screened on small scales, as in chameleon or symmetron scenarios. We present an analogy between thin shell configurations of such scalar fields…
We show that the chameleon scalar field can drive the current phase of cosmic acceleration for a large class of scalar potentials that are also consistent with local tests of gravity. These provide explicit realizations of a quintessence…
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…
The search for non-Newtonian forces has been pursued following many different paths. Recently it was suggested that hypothetical chameleon interactions, which might explain the mechanisms behind dark energy, could be detected in a…
We present the most recent results of both aspects of the GammeV experiment. The first aspect is a search for axion-like particles using a variable baseline, "light-shining-through-a-wall" technique. This search excludes the particle…
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,…
We investigate the cosmological dynamics of the recently proposed extended chameleon models at both background and linear perturbation levels. Dynamical systems techniques are employed to fully characterize the evolution of the universe at…
We calculate the chameleon field potential for ultracold neutrons, bouncing on top of one or between two neutron mirrors in the gravitational field of the Earth. For the resulting non--linear equations of motion we give approximate…
Chameleon scalar fields can screen their associated fifth forces from detection by changing their mass with the local density. These models are an archetypal example of a screening mechanism, and have become an important target for both…
Starting from the assumption that the present accelerated expansion of the Universe is driven by a chameleon scalar field, the function describing a direct coupling between the matter content of the Universe and the scalar field is derived…
Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor…
The nature of dark energy is one of the most outstanding problems in physical science, and various theories have been proposed. It is therefore essential to directly verify or rule out these theories experimentally. However, despite…
Scalar-tensor theories whose phenomenology differs significantly from general relativity on large (e.g. cosmological) scales do not typically pass local experimental tests (e.g. in the solar system) unless they present a suitable "screening…
Atom interferometry experiments are searching for evidence of chameleon scalar fields with ever-increasing precision. As experiments become more precise, so too must theoretical predictions. Previous work has made numerous approximations to…
Theories of modified gravity where light scalars with non-trivial self-interactions and non-minimal couplings to matter-chameleon and symmetron theories-dynamically suppress deviations from general relativity in the solar system. On other…
Current acceleration of the cosmic expansion leads to coincidence as well as fine-tuning issues in the framework of general relativity. Dynamical scalar fields have been introduced in response of these problems, some of them invoking…
In this article we study the properties of the flat FRW chameleon cosmology in which the cosmic expansion of the Universe is affected by the chameleon field and dark energy. In particular, we perform a detailed examination of the model in…
We propose a novel neutron interferometry setup to explore the potential existence of mirror neutrons, a candidate for dark matter. Our work demonstrates that if mirror neutrons exist, neutrons will acquire an observable geometric phase due…
We consider the potential detection of chameleons using bouncing ultracold neutrons. We show that the presence of a chameleon field over a planar plate would alter the energy levels of ultra cold neutrons in the terrestrial gravitational…
We present a detailed analysis of the phase-space for the field equations in scalar field cosmology with a chameleon cosmology in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker spacetime. For the matter source we assume that…