Two-fluid evolving Lorentzian wormholes

TL;DR

This paper studies the evolution of Lorentzian wormholes supported by two matter components, analyzing their expansion behavior under various conditions and generalizing previous single-fluid models.

Contribution

It introduces a two-fluid model for evolving wormholes, extending previous single-fluid models and analyzing their expansion under energy conditions.

Findings

Wormholes expand with constant velocity under certain conditions.

Expansion rate depends on the isotropic matter component or cosmological constant.

The model satisfies dominant and strong energy conditions in the entire spacetime.

Abstract

We investigate the evolution of a family of wormholes sustained by two matter components: one with homogeneous and isotropic properties $\rho(t)$ and another inhomogeneous and anisotropic $\rho_{in}(t,r)$. The rate of expansion of these evolving wormholes is only determined by the isotropic and homogeneous matter component $\rho(t)$. Particularly, we consider a family of exact two-fluid evolving wormholes expanding with constant velocity and satisfying the dominant and the strong energy conditions in the whole spacetime. In general, for the case of vanishing isotropic fluid $\rho(t)$ and cosmological constant $\Lambda$ the space expands with constant velocity, and for $\rho(t)=0$ and $\Lambda \neq 0$ the rate of expansion is determined by the cosmological constant. The considered here two-fluid evolving wormholes are a generalization of single fluid models discussed in previous works of the present authors [Phys.\ Rev.\ D {\bf 78}, 104006 (2008); Phys.\ Rev.\ D {\bf 79}, 024005 (2009)].