The world wide eeorts for detecting gravitational waves, the detectors in vogue and the expected astrophysical sources of gravitational waves will be discussed. Ground based detectors especially, the resonant bar detectors and laser interferometers will be described with a brief mention of the space based detector (the LISA project). Astrophysical sources of gravitational waves such as coalesci...

To investigate how chaos affects gravitational waves, we study the gravitational waves from a spinning test particle moving around a Kerr black hole, which is a typical chaotic system. To compare the result with those in non-chaotic dynamical system, we also analyze a spinless test particle, which orbit can be complicated in the Kerr back ground although the system is integrable. We estimate th...

An enigmatic prediction of Einstein’s general theory of relativity are gravitational waves. With the observed decay in the orbit of the Hulse-Taylor binary pulsar agreeing within a fraction of a percent with the theoretically computed decay from Einstein’s theory the existence of gravitational waves was firmly established. Currently there is a worldwide effort to detect gravitational waves with...

We describe gravitational lensing by a gravitational wave, in the regime in which multiple images of a light source are created. We adapt the vector formalism employed for ordinary gravitational lenses to the case of a non–stationary spacetime, and we derive an approximate condition for multiple imaging. It is shown that certain astrophysical sources of gravitational waves satisfy this conditio...

In many models of inflation, the period of accelerated expansion ends with preheating, a highly non-thermal phase of evolution during which the inflaton pumps energy into a specific set of momentum modes of field(s) to which it is coupled. This necessarily induces large, transient density inhomogeneities which can source a significant spectrum of gravitational waves. In this paper, we consider ...

Gravitational waves provide a laboratory for general relativity and a window to energetic astrophysical phenomena invisible with electromagnetic radiation. Several terrestrial detectors are currently under construction, and a space-based interferometer is envisioned for launch early next century to detect test-mass motions induced by waves of relatively short wavelength. Very-long-wavelength gr...

Gravitational waves are propagating fluctuations of gravitational fields, that is, ”ripples” in spacetime, generated mainly by moving massive bodies. These distortions of spacetime travel with the speed of light. Every body in the path of such a wave feels a tidal gravitational force that acts perpendicular to the waves direction of propagation; these forces change the distance between points, ...

The question whether gravitational waves are quantised or not can in principle be answered by the help of correlation measurements. If the gravitational waves are quantised and they are generated by the change of the background metrics then they can be in squeezed state. In a sqeezed state there is a correlation between the phase of the wave and the quantum fluctuations. It is recommended to an...

Gravity is one of the fundamental forces of Nature, and it is the dominant force in most astronomical systems. In common with all other phenomena, gravity must obey the principles of Special Relativity. In particular, gravitational forces must not be transmitted or communicated faster than light. This means that when the gravitational field of an object changes, the changes ripple outwards thro...

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...