Related papers: Neutron stars and the cosmological constant proble…
It has been suggested recently that the Hubble tension could be eliminated by a sharp, $\sim 10\%$ increase of the effective gravitational constant at $z \sim 0.01$. This would decrease the luminosities of type 1a supernovae in just the…
We investigate a conformal invariant gravitational model which is taken to hold at pre-inflationary era. The conformal invariance allows to make a dynamical distinction between the two unit systems (or conformal frames) usually used in…
We analyze effects of neutron-antineutron transitions in neutron stars, specifically on (i) cooling, (ii) rotation rate, and (iii) for binary pulsars, the increase in the orbital period. We show that these effects are negligibly small.
Regarding a $d-$dimensional spherically symmetric line element in the context of Einstein-$\Lambda$ gravity, the hydrostatic equilibrium equation of stars is obtained. Then, by using the lowest order constrained variational (LOCV) method…
In recent years, there have been several successful attempts to constrain the equation of state of neutron star matter using input from low-energy nuclear physics and observational data. We demonstrate that significant further restrictions…
We consider further consequences of recently [1] revealed role of cosmological constant \Lambda as of a physical constant, along with the gravitational one to define the gravity i.e. the General Relativity and its low-energy limit. We now…
In the presence of strong magnetic field reported to have been observed on the surface of some neutron stars and on what are called Magnetars, a host of physical phenomenon from the birth of a neutron star to free streaming neutrino cooling…
In this work we suggest, without detailed mathematical analysis, a hypothesis on the physical meaning of cosmological constant. It is primarily based on a conceptual analogy with energy characteristics of the crystal lattice structure, i.e.…
We study the effect of superfluidity on the tidal response of a neutron star in a general relativistic framework. In this work, we take a dual-layer approach where the superfluid matter is confined in the core of the star. Then, the…
As mature neutron stars are cold (on the relevant temperature scale), one has to carefully consider the state of matter in their interior. The outer kilometer or so is expected to freeze to form an elastic crust of increasingly neutron-rich…
One hope to solve the cosmological constant problem is to identify a symmetry principle, based on which the cosmological constant can be reduced either to zero, or to a tiny value. Here, we note that requiring that the vacuum state is…
Neutrinos play a crucial role in many aspects of astrophysics and cosmology. Since they control the electron fraction, or equivalently neutron-to-proton ratio, neutrino properties impact yields of r-process nucleosynthesis. Similarly the…
We outline the evaluation of the cosmological constant in the framework of the standard field-theoretical treatment of vacuum energy and discuss the relation between the vacuum energy problem and the gauge-group spontaneous symmetry…
The principles of General Relativity allow for a non-vanishing cosmological constant, which can possibly be interpreted at least partially in terms of quantum-fluctuations of matter fields. Depending on sign and magnitude it can cause…
The cosmological constant problem is principally concerned with trying to understand how the zero-point energy of quantum fields contributes to gravity. Here we take the approach that by addressing a fundamental unresolved issue in quantum…
The possibility that the vacuum energy density (VED), $\rho_{\rm vac}$, could be time dependent in the expanding Universe is intuitively more reasonable than just a rigid cosmological constant for the entire cosmic history. The dynamics of…
I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum tensor formally diverges as $k^4$. A cutoff…
Low-energy neutrinos from the cosmic background are captured by objects in the sky that contain material susceptible of single beta decay. Neutrons, which compose most of a neutron star, capture low-energy neutrinos from the cosmic neutrino…
There are many factors that contribute to the breaking of the spherical symmetry of a neutron star. Most notably is rotation, magnetic fields, and/or accretion of matter from companion stars. All these phenomena influence the macroscopic…
Quantum Chromodynamics (QCD) is the fundamental theory describing the strong nuclear force and the interactions among quarks and gluons. Topological stars, characterized by extreme density conditions, offer a unique environment where QCD…