Non-supersymmetric Tachyon-free Type-II and Type-I Closed Strings from RCFT

TL;DR

This paper explores non-supersymmetric four-dimensional closed string theories built from N=2 minimal models, demonstrating methods to eliminate tachyons through specific partition functions and Klein bottle projections.

Contribution

It provides a systematic construction of tachyon-free non-supersymmetric closed string theories using tensor products of N=2 minimal models and various projection techniques.

Findings

Many tachyon-free models identified

Methods to remove tachyons via partition functions

Methods to remove tachyons via Klein bottle projections

Abstract

We consider non-supersymmetric four-dimensional closed string theories constructed out of tensor products of N=2 minimal models. Generically such theories have closed string tachyons, but these may be removed either by choosing a non-trivial partition function or a suitable Klein bottle projection. We find large numbers of examples of both types.