Can one restore Lorentz invariance in quantum N=2 string?

TL;DR

This paper investigates whether Lorentz invariance can be restored in quantum N=2 string theory by analyzing its embedding into the N=4 topological framework, concluding that Lorentz covariant boson emission vertices cannot be constructed.

Contribution

It demonstrates the impossibility of constructing Lorentz covariant boson emission vertices within the N=4 topological formalism for quantum N=2 strings.

Findings

No Lorentz covariant boson emission vertex can be constructed.

Causality and cyclic symmetry constraints are key to the argument.

Lorentz invariance cannot be restored in this framework.

Abstract

We consider quantum N=2 string embedded into the N=4 topological framework from the perspective of the old covariant quantisation. Making use of the causality and cyclic symmetry of tree amplitudes we argue that no Lorentz covariant boson emission vertex can be constructed within the N=4 topological formalism.