Line data    Source code

       1           1 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : /// \file
       5             : /// Documents the `sgb` namespace
       6             : 
       7             : #pragma once
       8             : 
       9             : /*!
      10             :  * \brief Holds items related to Einstein-scalar-Gauss-Bonnet gravity.
      11             :  *
      12             :  * Einstein-scalar-Gauss-Bonnet is a modified gravity theory featuring a real
      13             :  * scalar field nonminimally coupled to the metric. In this code we will follow
      14             :  * the conventions of \cite Nee2024bur , and write the action as
      15             :  * \begin{equation}
      16             :  *  S = \int_\Omega d^4 x \, \sqrt{-g} \biggl\{ \frac{\mathcal{R}}{16 \pi G}
      17             :  *    - \frac{1}{2} \bigl( \nabla_\mu \Psi \bigr) \bigl( \nabla^\mu \Psi \bigr)
      18             :  *    + \ell^2 F[\Psi] \mathcal{G} \biggr\}
      19             :  * \end{equation}
      20             :  * where \f$\mathcal{R}\f$ is the Ricci scalar, \f$G\f$ is the Newton's,
      21             :  * constant, \f$\Psi\f$ is the real scalar field, \f$F[\Psi]\f$ is its coupling
      22             :  * function, and \f$\mathcal{G}\f$ is the Gauss-Bonnet invariant.
      23             :  */
      24             : namespace ScalarTensor::sgb {}