We study the radiation reaction on cosmic strings due to the emission of dilatonic, gravitational and axionic waves. After verifying the (on average) conservative nature of the time-symmetric self-interactions, we concentrate on the finite radiation damping force associated with the half-retarded minus half-advanced “reactive” fields. We revisit a recent proposal of using a “local back reaction...

In this paper we are going to examine the effect, if any exists, that a modification of the Schwarzchild metric by a lamda term could have on the so called Sakharov’s upper temperature limit. It’s known that Zakharov’s limit is the maximum possible black body temperature that can occur in our universe. Introduction: In 1966 Sakharov first came up with an upper temperature bound for the black bo...

The paper gives an introduction to the gravitational radiation theory of isolated sources and to the propagation properties of light rays in radiative gravitational fields. It presents a theoretical study of the generation, propagation, back–reaction, and detection of gravitational waves from astrophysical sources. After reviewing the various quadrupole–moment laws for gravitational radiation i...

We study the radiation reaction on cosmic strings due to the emission of dilatonic, gravitational and axionic waves. After discussing the renormalization of the string tension induced by time-symmetric self-interactions (thereby correcting errors in the literature concerning the effect of the dilaton field), we concentrate on the finite radiation damping force associated with the halfretarded m...

Cherenkov radiation may occur whenever the source is moving faster than waves it generates. In a dominated universe, with equation-of-state $w = 1/3$, we have recently shown that Bardeen scalar-metric perturbations contribute to linearized Weyl tensor in such manner its wavefront propagates at acoustic speed $\sqrt{w}=1/\sqrt{3}$. this work, explicitly compute shape of cone and wedge generated ...

Robinson-Wilczek’s recent work, which treats Hawking radiation as a compensating flux to cancel gravitational anomaly at the horizon of a Schwarzschild-type black hole, is extended to study Hawking radiation of rotating black holes in anti-de Sitter spaces, especially that in dragging coordinate system, via gauge and gravitational anomalies. The results show that in order to restore gauge invar...

A characteristic spectrum of relic gravitational radiation is produced by a period of ‘‘stringy inflation’’ in the early Universe. This spectrum is unusual, because the energy density rises rapidly with frequency. We show that correlation experiments with the two gravitational-wave detectors being built for the Laser Interferometric Gravitational Wave Observatory could detect this relic radiati...

A brief but broad survey is presented of the flows, forms and large-scale transformations of mass-energy in the universe, spanning a range of about twenty orders of magnitude (≈ mP lanck/mproton) in space, time and mass. Forms of energy considered include electromagnetic radiation, magnetic fields, cosmic rays, gravitational energy and gravitational radiation, baryonic matter, dark matter, vacu...

We present a novel nonlinear mechanism for exciting a gravitational radiation pulse (or a gravitational wave) by dust magnetohydrodynamic (DMHD) waves in dusty astrophysical plasmas. We derive the relevant equations governing the dynamics of nonlinearly coupled DMHD waves and a gravitational wave (GW). The system of equations is used to investigate the generation of a GW by compressional Alfvén...