相关论文: Shock-Wave Refinement of the Friedmann-Robertson-W…
We construct the simplest solution of the Einstein equations that incorporates a shock-wave into a standard Friedmann-Robertson-Walker metric whose equation of state accounts for the Hubble constant and the microwave background radiation…
We construct a class of global exact solutions of the Einstein equations that extend the Oppeheimer-Snyder (OS) model to the case of non-zero pressure, {\em inside the Black Hole}, by incorporating a shock wave at the leading edge of the…
We construct exact, entropy satisfying shock wave solutions of the Einstein equations for a perfect fluid which extend the Oppeheimer-Snyder (OS) model to the case of non-zero pressure, {\it inside the Black Hole}. These solutions put forth…
This paper concerns the construction and analysis of a new family of exact general relativistic shock waves. The construction resolves the open problem of determining the expanding waves created behind a shock-wave explosion into a static…
We prove that the Einstein equations in Standard Schwarzschild Coordinates close to form a system of three ordinary differential equations for a family of spherically symmetric, self-similar expansion waves, and the critical ($k=0$)…
We investigate shock-wave solutions of the Einstein equations in the case when the speed of propagation is equal to the speed of light. The work extends the shock matching theory of Smoller and Temple, which characterizes solutions of the…
The evolution of the closed Friedmann Universe with a packet of short scalar waves is considered with the help of the Wheeler--DeWitt equation. The packet ensures conservation of homogeneity and isotropy of the metric on average. It is…
Modern cosmological theory is based on the Friedmann--Robertson--Walker (FRW) metric. Often written in terms of co-moving coordinates, this well-known solution to Einstein's equations owes its elegant and highly practical formulation to the…
We study the asymptotic behaviour of solutions to the linear wave equation on cosmological spacetimes with Big Bang singularities and show that appropriately rescaled waves converge against a blow-up profile. Our class of spacetimes…
The Cosmological Principle is applied to a five-dimensional vacuum manifold. The general (non-trivial) solution is explicitly given. The result is a unique metric, parametrized with the sign of the space curvature ($k=0,\pm 1$) and the…
The usual Einstein's equations is modified as a one parameter family of equations in the framework of rainbow gravity. In this paper we derive the modified Friedmann-Robertson-Walker (FRW) equations when the cosmological evolution of…
Cosmological redshift z grows as the Universe expands and is conventionally viewed as a third form of redshift, beyond the more traditional Doppler and gravitational effects seen in other applications of general relativity. In this paper,…
We derive a new set of equations which describe a continuous one parameter family of expanding wave solutions of the Einstein equations such that the Friedmann universe associated with the pure radiation phase of the Standard Model of…
We consider space-times with two isometries which represent gravitational waves with distinct wavefronts which propagate into exact Friedmann-Robertson-Walker (FRW) universes. The geometry of possible wavefronts is analysed in detail in all…
In this article, we continue our investigation on how the electromagnetic waves propagate in the Friedman-Lemaitre-Robertson-Walker spacetime. Unlike the standard approach, which relies on null geodesics and geometric optics approximation,…
Robertson-Walker spacetimes within a large class are geometrically extended to larger cosmologies that include spacetime points with zero and negative cosmological times. In the extended cosmologies, the big bang is lightlike, and though…
We show that modelling the universe as a pre-geometric system with emergent quantum modes, and then constructing the classical limit, we obtain a new account of space and gravity that goes beyond Newtonian gravity even in the…
We consider general-relativistic rotational perturbations in homogeneous and isotropic Friedman - Robertson - Walker (FRW) cosmologies. Taking linear perturbations of FRW models, the general solution of the field equations contains…
We study the conditions for the consistency of the Friedmann-Robertson-Walker (FRW) metric with the dynamical Chern-Simons modified gravity. It turns out to be that in this situation the accelerated expansion of the Universe takes place,…
We derive the effects of a non-zero cosmological constant $\Lambda$ on gravitational wave propagation in the linearized approximation of general relativity. In this approximation we consider the situation where the metric can be written as…