相关论文: Weakly-coupled metastable graviton

Cascading gravity is an explicit realization of the idea of degravitation, where gravity behaves as a high-pass filter. This could explain why a large cosmological constant does not backreact as much as anticipated from standard General…

We summarise highlights from an ongoing research programme that aims, in the long run, at the ambitious goal of building a realistic, complete holographic composite-Higgs model. This contribution focuses on vacuum misalignment, by showing…

We consider a two-dimensional nonlinear waveguide with distributed gain and losses. The optical potential describing the system consists of an unperturbed complex potential depending only on one transverse coordinate, i.e., corresponding to…

In 3+1 space-time dimensions, fourth order derivative gravity is perturbatively renormalizable. Here it is shown that it describes a unitary theory of gravitons (with/without an additional scalar) in a limited coupling parameter space which…

We derive the modified Friedmann equations for a generalization of the Dvali-Gabadadze-Porrati (DGP) model in which the brane has one additional compact dimension. The main new feature is the emission of gravitational waves into the bulk.…

General Relativity can be reformulated as a diffeomorphism invariant gauge theory of the Lorentz group, with Lagrangian of the type $f(F\wedge F)$, where $F$ is the curvature 2-form of the spin connection. A theory from this class with a…

We study the growth of subhorizon perturbations in brane-induced gravity using perturbation theory. We solve for the linear evolution of perturbations taking advantage of the symmetry under gauge transformations along the extra-dimension to…

We develop a theory for light propagating in an atomic Bose-Einstein condensate in the presence of strong interactions. The resulting many-body correlations are shown to have profound effects on the optical properties of this interacting…

We show the generic existence of metastable massive gravitons in the four-dimensional core of self-gravitating hypermonopoles in any number of infinite-volume extra-dimensions. Confinement is observed for Higgs and gauge bosons couplings of…

We consider a collection of weakly interacting diffusion processes moving in a two-scale locally periodic environment. We study the large deviations principle of the empirical distribution of the particles' positions in the combined limit…

The perturbation theory with a variational basis is constructed and analyzed.The generalized Gaussian effective potential is introduced and evaluated up to the second order for selfinteracting scalar fields in one and two spatial…

We study the possibility of realizing a growth rate of matter density perturbations lower than that in General Relativity. Using the approach of the effective field theory of modified gravity encompassing theories beyond Horndeski, we…

Under the assumptions of General Relativity (GR), gravitational waves propagate at the speed of light and their mediation can be represented as a particle through a massless graviton. We investigate the impact and observability of the…

Post-Newtonian theory is considered a reliable effective expansion of General Relativity in the weak-field and slow-motion limit. We argue that such a belief is misplaced. In generic many-body relativistic dynamics, the absence of globally…

We study graviton-photon conversion in the presence of stochastic magnetic fields. Assuming Gaussian magnetic fields that may possess nontrivial helicity, and unpolarized gravitational waves (GWs) as the initial state, we obtain expressions…

By considering linear-order departures from general relativity, we compute a novel expression for the weak lensing convergence power spectrum under alternative theories of gravity. This comprises an integral over a 'kernel' of general…

Whenever fields are allowed to propagate in different portions of space-time, the four dimensional theory exhibits an effective violation of the principle of equivalence. We discuss the conditions under which such an effect is relevant for…

We investigate the propagation of gravitational waves in the context of fourth order gravity nonminimally coupled to a massive scalar field. Using the damping of the orbital period of coalescing stellar binary systems, we impose constraints…

Linearized gravity in the Very Special Relativity (VSR) framework is considered. We prove that this theory allows for a non-zero graviton mass $m_g$ without breaking gauge invariance nor modifying the relativistic dispersion relation. We…

Polarization of electromagnetic waves carries a large amount of information about their astrophysical emitters and the media they passed through, and hence is crucial in various aspects of astronomy. Here we demonstrate an important but…