# Superstrings in 2D Backgrounds with R-R Flux and New Extremal Black Holes

**Authors:** Nathan Berkovits, Sergei Gukov, Brenno Carlini Vallilo  
**arXiv:** [hep-th/0107140](https://arxiv.org/abs/hep-th/0107140)  
**Date:** 2001-07-17  
**Summary page:** https://www.summarizepaper.com/en/paper/hep-th--0107140v3/

## Key points

- Authors Nathan Berkovits, Sergei Gukov, and Brenno Carlini Vallilo focus on superstring theory in two-dimensional target spaces
- They utilize the hybrid formalism to quantize the superstring while maintaining spacetime supersymmetry
- Construct a sigma model action for Type II superstrings in curved two-dimensional supergravity backgrounds with Ramond-Ramond flux
- Investigate Calabi-Yau four-fold compactifications with Ramond-Ramond flux
- Explore new extremal black hole solutions within two-dimensional dilaton supergravity theory, extending the CGHS model
- Speculate on using a supergroup version of the SL(2,R)/U(1) WZW model to describe these novel black holes
- Study dynamic aspects of these black holes, including formation and evaporation processes
- The paper expands understanding of string theory in two-dimensional backgrounds and highlights the interplay between string theory and gravitational phenomena

## Summary

In their paper "Superstrings in 2D Backgrounds with R-R Flux and New Extremal Black Holes," authors Nathan Berkovits, Sergei Gukov, and Brenno Carlini Vallilo delve into the realm of superstring theory within two-dimensional target spaces. Utilizing the hybrid formalism, they embark on a journey to quantize the superstring in a manner that maintains spacetime supersymmetry. This leads them to construct a sigma model action specifically tailored for the Type II superstring existing within curved two-dimensional supergravity backgrounds. These backgrounds are not limited in scope; they can incorporate Ramond-Ramond flux, opening up a plethora of possibilities for exploration. One intriguing avenue pursued by the authors involves investigating Calabi-Yau four-fold compactifications with Ramond-Ramond flux. Additionally, they delve into the realm of new extremal black hole solutions within the framework of two-dimensional dilaton supergravity theory. These black hole solutions represent a significant advancement and serve as a natural extension of the CGHS model. The authors even speculate on the potential use of a supergroup version of the SL(2,R)/U(1) WZW model to describe these novel black holes. Beyond proposing theoretical constructs, Berkovits, Gukov, and Vallilo also dedicate attention to studying dynamic aspects associated with these newfound black holes. They explore phenomena such as formation and evaporation processes, shedding light on how these exotic solutions evolve over time. Overall, this paper expands our understanding of superstring theory in two-dimensional backgrounds and offers tantalizing insights into the interplay between string theory and gravitational phenomena like extremal black holes. By merging concepts from different branches of theoretical physics, this work paves the way for further investigations at the intersection of string theory and gravity.