Particle creation by a massless spin-$\frac{1}{2}$ field in a warped cosmological braneworld scenario

TL;DR

This paper investigates how a massless spin-1/2 field in a five-dimensional warped cosmological spacetime leads to particle creation, with effects localized on branes, using adiabatic regularization to analyze the energy-momentum tensor.

Contribution

It introduces a method to analyze particle creation in a dynamic warped braneworld with a time-dependent extra dimension, extending previous four-dimensional results.

Findings

Energy density is localized along the extra dimension.

Warping factor influences the amount of created matter.

Dynamic extra dimension affects the stress-energy tensor.

Abstract

Energy momentum tensor of a quantized massless bulk spin-$\frac{1}{2}$ field in five dimensional warped cosmological spacetimes is studied. The four dimensional part of our model represents a warped cosmological thick brane and the scale of the extra dimension is time-dependent. We use a simple ansatz to solve the Dirac equation in the bulk that helps us to compare our results with the known four dimensional case. Renormalisation of the components of the energy momentum tensor is achieved using adiabatic regularization method. We compute the leading order finite contribution to the stress-energy tensor which is of adiabatic order six. The resulting energy and pressure densities explicitly show the effects of the so-called warping factor and the dynamic extra dimension on the created matter. We show how the energy density produced are localized to form 3-branes along the extra dimension.