Vacuum Energy in Non-Supersymmetric Quasi-Realistic Heterotic-String Vacua with Fixed Moduli

TL;DR

This paper investigates the vacuum energy in non-supersymmetric heterotic-string models with fixed moduli, using the Free Fermionic Formalism to analyze models with various potential signs at one-loop.

Contribution

It introduces a class of quasi-realistic heterotic-string vacua with fixed moduli, analyzing their vacuum energy through asymmetric boundary conditions and GSO projections.

Findings

Models exhibit both positive and negative one-loop spacetime potential.

Moduli are projected out, leading to fixed moduli in the models.

Analysis includes both tachyon-free and tachyonic compactifications.

Abstract

Recently, Baykara, Tarazi and Vafa discussed the existence of quasicrystalline string vacua that contain a single neutral moduli, the dilaton, and studied compactifications of the non-supersymmetric $SO(16)\times SO(16)$ heterotic-string on these spaces. We discuss a specific class of quasi-realistic string vacua with similar properties that has been known since the late eighties and analyse the vacuum energy in several non-supersymmetric examples that correspond to compactifications of tachyon free ten dimensional vacua as well as compactifications of tachyonic ten dimensional vacua. Our analysis uses the Free Fermionic Formalism of the heterotic-string in four dimensions and employs asymmetric boundary conditions that project all the geometrical moduli by Generalised GSO projections. This methodology produces models with both positive and negative spacetime potential at one-loop.