Reference Level of the Vacuum Energy Density of the Universe and Astrophysical Data

Abstract

An extended framework of gravity, in which the first Friedmann equation is satisfied up to some constant due to violation of gauge invariance, is tested against astrophysical data: Supernovae Type‐Ia, Cosmic Chronometers, and Gamma‐ray bursts. A generalized expression for the Friedmann equation, including the possible vacuum contributions, is suggested, and two particular cosmological models with two independent parameters are considered within this framework and compared on the basis of the likelihood analysis. One of the models considered includes contribution of the residual vacuum fluctuations to the energy density and places the limit on the UV cutoff scale as , where is the number of minimally coupled scalar fields. Model comparison using the Akaike information criteria and Bayesian evidence shows a preference for the conventional ΛCDM over the extended models. A more general model with three parameters is considered within which an anti‐correlated behavior between the dynamical vacuum fluctuations contribution and a negative cosmological constant was found. The result is an upper limit of at 95% C.L., which is only mildly disfavored () with respect to ΛCDM.

A Vacuum of Quantum Gravity That is Ether.

“…Using this equation of vacuum state leads to the universe behavior at early times, when the scale factor was small, as freely rolling, i.e., without any deceleration or acceleration. That implies the zero-level deceleration parameter q(a) at small scale factors a [28][29][30][31], as it is shown in Fig. 1 (right panel).…”

Vacuum Polarization Instead of “Dark Matter” in a Galaxy

“…Other contributors to the vacuum energy density are the terms depending on the derivatives of the universe expansion rate [10,41,42,46]. They have the correct order of magnitude ρ v ∼ M 2 p H 2 , where H is the Hubble constant, and explain the accelerated expansion of the universe driven by the residual energy density and pressure [10,41,42,46]:…”

“…Eqs. (10) include the number of minimally coupled scalar fields N sc plus two degrees of freedom of the gravitational waves [41]. The massless fermions and photons do not contribute to (10) [41].…”

“…That is possible because the equations for evolution of the Hamiltonian H and the momentum constraints P admit not only the trivial solution P = 0, H = 0, but also P = 0, H = const. The constant compensates for the main part of the vacuum energy density proportional to the Planck mass in the fourth degree [8,10]. Residual energy density, remaining after omitting the main part of the vacuum energy density, is some kind of dark energy and results in a cosmological picture containing a period of linear evolution in cosmic time [10,11] followed by late accelerated expansion.…”

Eicheons instead of Black holes

“…That is the unimodular gravity [35][36][37][38][39], which admits an arbitrary cosmological constant. However, under using of the comoving momentums cutoff, the vacuum energy density scales with time as radiation [34], but not as the cosmological constant.…”