Related papers: The Effective Fluid approach for Modified Gravity …
Effective field theories offer a powerful method to unify diverse models under a small set of control parameters, allowing systematic expansions around well-established theories. These techniques, developed in particle physics, were…
Theoretical results on a conventional approach to the dark energy (DE) concept are reviewed and discussed. According to them, there is absolutely no need for a novel DE component in the Universe, provided that the associated matter-energy…
In this paper, we have investigated the anisotropic behavior of the accelerating universe in Bianchi V space time in the frame work of General Relativity (GR). The matter field we have considered is of two non interacting fluids i.e. the…
We study the cosmological evolution based upon a $D$-dimensional action in low-energy effective string theory in the presence of second-order curvature corrections and a modulus scalar field (dilaton or compactification modulus). A…
We study the imprints of an effective dark energy fluid in the large scale structure of the universe through the observed angular power spectrum of galaxies in the relativistic regime. We adopt the phenomenological approach that introduces…
This paper explores the quantum-fluid correspondence in a charged relativistic fluid with intrinsic spin. We begin by examining the nonrelativistic case, showing that the inclusion of spin introduces a quantum correction to the classical…
Charged fluids rotating around compact objects can form unique equilibrium structures when ambient large-scale electromagnetic fields combine with strong gravity. Equatorial as well as off-equatorial toroidal structures are among such…
We suggest a Lorentz non-invariant generalization of the unimodular gravity theory, which is classically equivalent to general relativity with a locally inert (devoid of local degrees of freedom) perfect fluid having an equation of state…
Following our previous work wherein the leading order effective action was computed in the covariant effective field theory of gravity, here we specialize the effective action to the FRW spacetime and obtain the effective Friedmann…
The effective field theory of cosmological perturbations stems from considering a cosmological background solution as a state displaying spontaneous breaking of time translations and (adiabatic) perturbations as the related Nambu-Goldstone…
We derive new cosmological solutions of the ghost-free massive gravity with a general background metric in which the contribution of the mass sector to the metric one is modeled by an effective cosmological constant and an ideal fluid which…
The cosmological constant and its phenomenology remain among the greatest puzzles in theoretical physics. We review how modifications of Einstein's general relativity could alleviate the different problems associated with it that result…
This article examines the foundation of the recently developed relativistic variational formalism[1]. Our work is heavily based on [2, 27] which extends this approach to the multi-fluid theory and examines its utility in astrophysics and…
Canonical methods can be used to construct effective actions from deformed covariance algebras, as implied by quantum-geometry corrections of loop quantum gravity. To this end, classical constructions are extended systematically to…
The effective theory of the Anton-Schmidt cosmic fluid within the Debye approximation is investigated. In this picture, the universe is modeled out by means of a medium without cosmological constant. In particular, the Anton-Schmidt…
We review the effective field theory (EFT) approach to gravitational dynamics. We focus on extended objects in long-wavelength backgrounds and gravitational wave emission from spinning binary systems. We conclude with an introduction to EFT…
Empirical theories of Dark Matter like MOND gravity and of Dark Energy like f(R) gravity were motivated by astronomical data. But could these theories be branches rooted from a more general hence natural framework? Here we propose the…
In this letter a new formula for light deflection is derived using only physically observable concepts. The general result is specialized to cosmological perturbation theory and expressed in terms of gauge--invariant perturbation variables.…
The starting point in this note is $f(R)$ modified gravity in a cosmological setting. We assume a spatially flat Universe to describe late-time cosmology and the perfect-fluid equation of state $p=\omega\rho$ to model the hypothesized dark…
In this mini-review we discuss first why we should investigate cosmological models beyond LCDM. We then show how to describe dark energy or modified gravity models in a fluid language with the help of one background and two perturbation…