相关论文: Vacuum polarization around stars: nonlocal approxi…
We study the effect of vacuum polarization in nuclear reactions of astrophysical interest. This effect has the opposite sign compared to the screening by the atomic electrons. It is shown that vacuum polarization further increases the…
In this paper we investigate the vacuum polarization effects associated with a massive quantum scalar field in de Sitter spacetime in the presence of gravitational topological defects. Specifically we calculate the vacuum expectation value…
We numerically construct compact stars in the scalar-tensor theory of gravity with non-minimal derivative coupling of a scalar field to the curvature and nonzero cosmological constant. There are two free parameters in this model of gravity:…
In order to investigate the effects of vacuum polarisation on mass inflation singularities, we study a simple toy model of a charged black hole with cross flowing radial null dust which is homogeneous in the black hole interior. In the…
Non-rotating neutron stars are generally treated in theoretical studies as perfect spheres. Such a treatment, however, may not be correct if strong magnetic fields are present (such as for magnetars) and/or the pressure of the matter in the…
We study relativistic stars in the scale-dependent scenario, which is one of the approaches to quantum gravity, and where Newton's constant is promoted to a scale-dependent quantity. First, the generalized structure equations are derived…
This paper explores the theoretical implications of quantum gravity by analyzing compact stellar objects, presenting three distinct models that serve as alternatives to traditional black holes. These models are characterized by their…
Vacuum polarization of a massive scalar field in the background of a two-dimensional version of a spinning cosmic string is investigated. It is shown that when the `radius of the universe' is such that spacetime is globally hyperbolic the…
We study static, spherically symmetric neutron stars in a class of scalar-tensor theories with non-canonical kinetic terms (K-essence) obeying all causality and hyperbolicity conditions. These models have non-trivial dynamics that lead to a…
We investigate the cosmological coupling of spherical, local astrophysical systems. We derive a general formula quantifying the cosmological coupling of the Misner-Sharp mass of these objects. We show that, in the weak-field limit, the…
We compute the vacuum polarization energies for a couple of soliton models in one space and one time dimensions. These solitons are mappings that connect different degenerate vacua. From the considered sample solitons we conjecture that the…
Stellar pulsations in rotating relativistic stars are reviewed. Slow rotation approximation is applied to solving the Einstein equations. The rotational effects on the non-axisymmetric oscillations are explicitly shown in the polar and…
We construct hydrogen atmosphere models for magnetized neutron stars in radiative equilibrium with surface fields B=10^12-5x10^14 G and effective temperatures T_eff a few x 10^5-10^6 K by solving the full radiative transfer equations for…
We perform a theoretical study of vacuum polarization corrections to the hyperfine structure in many-electron atoms. Calculations are performed for systems of interest for precision atomic tests of fundamental physics belonging to the…
We explore the effects of a positive cosmological constant on astrophysical and cosmological configurations described by a polytropic equation of state. We derive the conditions for equilibrium and stability of such configurations and…
The vacuum fluctuations of all quantum fields filling the universe are supposed to leave enormous energy and pressure contributions which are incompatible with observations. It has been recently suggested that, when the effective nature of…
Vacuum energy in quantum field theory, being the sum of zero-point energies of all field modes, is formally infinite but yet, after regularization or renormalization, can give rise to finite observable effects. One way of understanding how…
Gravitational field of cosmic strings in theories with extra spatial dimensions must differ significantly from that in the Einstein's theory. This means that all gravity induced properties of cosmic strings need to be revised too. Here we…
Cosmological consequences of the nonsymmetric gravitational theory (NGT) are studied. The structure of the NGT field equations is analyzed for an inhomogeneous and anisotropic universe, based on the spherically symmetric field equations. It…
In this paper we consider a charged massless scalar quantum field operator in the spacetime of an idealized cosmic string, i.e., an infinitely long, straight and static cosmic string, which presents a magnetic field confined in a…