Exact gravitational lensing by cosmic strings with junctions

TL;DR

This paper extends previous findings on the geometry around cosmic strings with junctions, demonstrating that the flatness result holds to all orders in string tension, not just linear order.

Contribution

It generalizes earlier linear-order results to show the geometry remains flat around cosmic strings with junctions at all orders in tension.

Findings

Geometry around cosmic strings with junctions is flat to all orders in tension.

Previous linear-order results are valid to all orders.

The extension simplifies understanding cosmic string effects on spacetime.

Abstract

We point out that the results by Brandenberger et al. in Phys.Rev.D77:083502(2008) that the geometry around the straight cosmic strings with stationary junctions is flat to linear order in the string tension can be immediately extended to any order.