# Actions for particles and strings and Chern-Simons gravity

## TL;DR

This paper explores actions for particles and strings using twistorial descriptions in Minkowski and AdS spaces, and examines collective dynamics in Chern-Simons theories, connecting geometric, gravitational, and fluid dynamics concepts.

## Contribution

It introduces a twistorial framework for particles and strings in 4d spacetimes and analyzes collective dynamics in Chern-Simons gravity, extending classical and modern theoretical approaches.

## Key findings

- Twistorial descriptions for particles and strings in Minkowski and AdS spaces.
- Analysis of collective coordinate dynamics in Chern-Simons theories.
- Potential links between Chern-Simons gravity and fluid-gravity correspondence.

## Abstract

We consider actions for particles and strings, including twistorial descriptions on 4d Minkowski and AdS$_5$ spacetimes from the point of view of co-adjoint orbits for the isometry group. We also consider the collective coordinate dynamics of singular solutions in Chern-Simons (CS) theories and CS theories of gravity. This is a generalization of the work of Einstein, Infeld and Hoffmann and also has potential points of contact with fluid-gravity correspondence.