Traversable wormhole for string, but not for particle

TL;DR

This paper introduces a Lorentzian wormhole geometry in string theory where strings can traverse the wormhole due to their chiral nature, unlike point particles which cannot cross the boundaries.

Contribution

It presents a novel wormhole solution in string theory with a unique geometry that allows string traversal but not particle traversal, highlighting string-specific effects.

Findings

Strings can traverse the wormhole, unlike particles.

The geometry involves a chiral string sector with non-Riemannian boundaries.

Point-particle geodesics are complete but non-traversable across regions.

Abstract

We propose a Lorentzian wormhole geometry characterized by a closed string massless sector with nontrivial $H$-flux and a scalar dilaton. In the string frame, the dilaton exhibits a negative kinetic term, enabling the existence of the wormhole. The geometry consists of three distinct regions. The middle region contains the throat, and its boundaries with the other two regions form non-Riemannian two-spheres, where a fundamental string becomes chiral, akin to a non-relativistic string. While point-particle geodesics are complete within each region and non-traversable across regions, strings perceive the geometry differently, allowing a chiral string to traverse freely.