An off-shell D-brane action at order $ \alpha'^2$ in flat spacetime

TL;DR

This paper derives an off-shell D-brane action at order α'^2 in flat spacetime by ensuring compatibility with T-duality and S-duality, advancing the understanding of D-brane dynamics in string theory.

Contribution

It presents a new off-shell D-brane action at order α'^2 consistent with duality symmetries, extending previous on-shell formulations.

Findings

Derived off-shell D-brane action at order α'^2

Ensured compatibility with T-duality and S-duality

Provides a basis for further studies of D-brane effective actions

Abstract

We use compatibility of the second fundamental form corrections to DBI action at order $\alpha'^2$ which includes trace of the second fundamental form, with T-duality and with the linear S-duality as guiding principles to find an off-shell D-brane action at order $\alpha'^2$ in type II superstring theories in flat spcetime.