Zero modes on cosmic string loops

TL;DR

This paper investigates the spectrum of fermionic modes on cosmic string loops and finds no zero or massive bound states, implying vortons stabilized by fermionic currents are unlikely to exist.

Contribution

It demonstrates the absence of fermionic zero modes and bound states on cosmic string loops and similar topological systems with zero net charge, challenging previous assumptions.

Findings

No fermionic zero modes on cosmic string loops

Absence of massive bound states on loops

Systems with zero net topological charge lack fermionic bound modes

Abstract

We study the spectrum of fermionic modes on cosmic string loops. We find no fermionic zero modes nor massive bound states - this implies that vortons stabilized by fermionic currents do not exist. We have also studied kink-(anti)kink and vortex-(anti)vortex systems and find that all systems that have vanishing net topological charge do not support fermionic bound modes.