The General Class of String Theories on Orbifolds

TL;DR

This paper establishes a comprehensive framework for constructing consistent string theories on orbifolds by analyzing key invariance and duality conditions, leading to a broad class of models including new ones.

Contribution

It introduces a set of three core consistency conditions that define the general class of orbifold string theories, expanding the known landscape.

Findings

Derived the general class of consistent orbifold models

Identified a new class of orbifold models

Confirmed the importance of invariance and duality conditions

Abstract

We investigate the following three consistency conditions for constructing string theories on orbifolds: i) the invariance of the energy-momentum tensors under twist operators, ii) the duality of amplitudes and iii) modular invariance of partition functions. It is shown that this investigation makes it possible to obtain the general class of consistent orbifold models, which includes a new class of orbifold models.