Some properties of the "String gas" with the equation of state $p = -\rho/3$

TL;DR

This paper explores the unique properties of a string gas with a specific equation of state, revealing its potential to alter universe topology, produce unusual geometries, and mimic dark matter effects in astrophysical contexts.

Contribution

It demonstrates the diverse effects of a string gas with p = -ρ/3 on cosmological and astrophysical structures, highlighting its theoretical significance.

Findings

String gas can change observable universe topology.

It produces bizarre geometries in spherically symmetric spacetimes.

Its influence on rotation curves mimics dark matter effects.

Abstract

We show that the string gas - a perfect fluid with the equation of state $p = -\frac13 \rho$ possesses rather interesing properties. In Friedmann universes its presence can can change the observable topology of the space; in the spherically symmetric spacetimes it produces rather bizzare geometries and in a way its influence on the rotation curves mimics the dark matter effects.