Stimulated radiation from axion cluster evolution in static spacetimes

Axion Radiation from Strings

This paper revisits the problem of the string decay contribution to the axion cosmological energy density. We show that this contribution is proportional to the average relative increase when axion strings decay of a certain quantity Nax which we define. We carry out numerical simulations of the evolution and decay of circular and non-circular string loops, of bent strings with ends held fixed,...

Spherically Symmetric Static Spacetimes

In this paper we discuss matter inheritance collineations by giving a complete classification of spherically symmetric static spacetimes by their matter inheritance symmetries. It is shown that when the energy-momentum tensor is degenerate, most of the cases yield infinite dimensional matter inheriting symmetries. It is worth mentioning here that two cases provide finite dimensional matter inhe...

Multipole Moments of Static Spacetimes

Scalar Field Quantum Inequalities in Static Spacetimes

We discuss quantum inequalities for minimally coupled scalar fields in static spacetimes. These are inequalities which place limits on the magnitude and duration of negative energy densities. We derive a general expression for the quantum inequality for a static observer in terms of a Euclidean two-point function. In a short sampling time limit, the quantum inequality can be written as the flat...

Quantum mechanical path integrals and thermal radiation in static curved spacetimes

Quantum mechanical path integrals [1–4], also called first quantised path integrals, have been applied to some problems in curved spacetimes [5], such as to cosmological and black-holes issues [6–11]. A remarkable theoretical prediction in semi-classical gravity is that of the thermal and quantum radiation of black holes [12,13]. This result is recovered again in the present paper within the fo...