Related papers: Charting the Fifth Force Landscape
Hidden variable graphical models can sometimes imply constraints on the observable distribution that are more complex than simple conditional independence relations. These observable constraints can falsify assumptions of the model that…
We study how the Vainshtein mechanism operates in the most general scalar-tensor theories with second-order equations of motion. The field equations of motion, which can be also applicable to most of other screening scenarios proposed in…
We study the effects of coupling a cosmologically rolling scalar field to higher order curvature terms. We show that when the strong coupling scale of the theory is on the 10^{-3}-10^{-1}eV range, the model passes all experimental bounds on…
Scalar fields with inverse power-law effective potentials may provide a negative pressure component to the energy density of the universe today, as required by cosmological observations. In order to be cosmologically relevant today, the…
It is shown that if our visible universe is a thin trapped shell in a five-dimensional universe, all matter in it may be connected almost instantaneously through the fifth dimension. What appears to be action at a distance is then…
When augmenting our cosmological models or gravitational theories with an additional light scalar field, any coupling between matter and this scalar can affect the orbital motion of binary systems. Ordinarily, the new force mediated by the…
Scalar-tensor theories are frequently only consistent with fifth force constraints in the presence of a screening mechanism, namely in order to suppress an otherwise unacceptably large coupling between the scalar and ordinary matter. Here…
The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark…
The observed accelerating universe indicates the presence of Dark Energy which is probably interpreted in terms of an extremely light gravitational scalar field. We suggest a way to probe this scalar field which contributes to optical…
We examine the possibility that dark matter may be the manifestation of dark forces of a hidden sector, i.e. "Dark Force = Dark Matter." As an illustrative and minimal example we consider the hidden SU(2)_h x U(1)_h gauge group. The hidden…
Chameleon scalar fields are dark energy candidates which suppress fifth forces in high density regions of the universe by becoming massive. We consider chameleon models as effective field theories and estimate quantum corrections to their…
We consider a cosmology in which dark matter and a quintessence scalar field responsible for the acceleration of the Universe are allowed to interact. Allowing for both conformal and disformal couplings, we perform a global analysis of the…
The area of research called \textquotedblleft Lineability\textquotedblright% \ looks for linear structures inside exotic subsets of vector spaces. In the last decade lineability/spaceability has been investigated in rather general settings;…
Scalar field dynamics may give rise to a nonzero cosmological variation of fundamental constants. Within different scenarios based on the unification of gauge couplings, the various claimed observations and bounds may be combined in order…
In the framework of special relativity (SR), I propose that matter conformally couples to a scalar field through the Lagrangian density of matter, whether matter is characterized by classical or by quantum (statistical) mechanics. The…
Chameleon dark energy is a matter-coupled scalar field which hides its fifth forces locally by becoming massive. We estimate torsion pendulum constraints on the residual fifth forces due to models with gravitation-strength couplings.…
Modifications of General Relativity generically contain additional degrees of freedom that can mediate forces between matter particles. One of the common manifestations of a fifth force in alternative gravity theories is a difference…
Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…
The potential existence of a fifth fundamental force, mediated by the X17 boson, has generated significant interest. This force can manifest itself as either a vector or pseudoscalar particle. In order to gain insight into the effective…
Fifth forces are ubiquitous in modified gravity theories, and must be screened to evade stringent local tests. This can introduce unusual behaviour in galaxy phenomenology by affecting galaxies' components differently. Here we use the…