T-duality equivalences beyond string theory

Understand

We examine a two parameter family of gravitational actions which contains higher-derivative terms.

• These are such that the entire action is invariant under corrected T-duality rules, which we derive explicitly.
• Generically this action does not describe low energy string backgrounds except for isolated choices for the parameters.
• Nevertheless, we demonstrate that in this theory the entropy and the temperature of generic black hole solutions are T-duality invariant.