$O(25,25)$ symmetry of bosonic string theory at order $\alpha'^2$

TL;DR

This paper demonstrates that the effective action of bosonic string theory at order α'^2 can be expressed in an O(25,25)-invariant form using cosmological reduction, extending previous symmetry considerations.

Contribution

It shows that the order α'^2 effective action can be written in an O(25,25) invariant form, confirming a larger symmetry structure in bosonic string theory.

Findings

Effective action at order α'^2 is O(25,25) invariant.

Cosmological reduction reveals symmetry structure.

Supports larger symmetry conjectures in string theory.

Abstract

It has been recently observed that the imposition of the $O(1,1)$ symmetry on the circle reduction of the classical effective action of string theory, can fix the effective action of the bosonic string theory at order $\alpha'^2$, up to an overall factor. In this paper, we use the cosmological reduction on the action and show that, up to one-dimensional field redefinitions and total derivative terms, it can be written in the $O(25,25)$-invariant form proposed by Hohm and Zwiebach.