Fermionic T-duality in fermionic double space

TL;DR

This paper interprets fermionic T-duality within a doubled fermionic space framework, revealing how duality transformations relate to permutations of fermionic coordinates and analyzing their effects on background fields and the dilaton.

Contribution

It generalizes the double space concept to fermionic sectors, providing a new geometric interpretation of fermionic T-duality in superstring theory.

Findings

Fermionic T-duality acts as permutation of fermionic coordinates.

Derived the form of fermionic T-dual NS-R and R-R background fields.

Analyzed the impact on the dilaton field in fermionic double space.

Abstract

In this article we offer the interpretation of the fermionic T-duality of the type II superstring theory in double space. We generalize the idea of double space doubling the fermionic sector of the superspace. In such doubled space fermionic T-duality is represented as permutation of the fermionic coordinates $\theta^\alpha$ and $\bar\theta^\alpha$ with the corresponding fermionic T-dual ones, $\vartheta_\alpha$ and $\bar\vartheta_\alpha$, respectively. Demanding that T-dual transformation law has the same form as inital one, we obtain the known form of the fermionic T-dual NS-R i R-R background fields. Fermionic T-dual NS-NS background fields are obtained under some assumptions. We conclude that only symmetric part of R-R field strength and symmetric part of its fermionic T-dual contribute to the fermionic T-duality transformation of dilaton field and analyze the dilaton field in fermionic double space. As a model we use the ghost free action of type II superstring in pure spinor formulation in approximation of constant background fields up to the quadratic terms.