SpECTRE  v2025.08.19
ScalarTensor::Tags::ScalarSourceCompute Struct Reference

Computes the source term given by the coupling of the scalar to curvature. More...

#include <ScalarSource.hpp>

Public Types

using argument_tags = tmpl::list< gr::Tags::WeylElectricScalar< DataVector >, gr::Tags::WeylMagneticScalar< DataVector >, CurvedScalarWave::Tags::Psi, ScalarTensor::Tags::CouplingParameters, ScalarTensor::Tags::ScalarMass, ScalarTensor::Tags::RampUpParameters, ::Tags::Time >
 
using return_type = Scalar< DataVector >
 
using base = ScalarSource
 
- Public Types inherited from ScalarTensor::Tags::ScalarSource
using type = Scalar< DataVector >
 

Static Public Attributes

static constexpr void(* function )(const gsl::not_null< Scalar< DataVector > * >, const Scalar< DataVector > &, const Scalar< DataVector > &, const Scalar< DataVector > &, const CouplingParameterOptions &, const double, const std::pair< double, double >, const double) = &gauss_bonnet_scalar_source
 

Detailed Description

Computes the source term given by the coupling of the scalar to curvature.

Details

For a scalar field with mass parameter \( m_\Psi \), the wave equation takes the form

\begin{align} \Box \Psi = \mathcal{S} ~, \end{align}

where the source is given by

\begin{align} \mathcal{S} \equiv m^2_\Psi \Psi - f'(\Psi) \mathcal{G}~, \end{align}

where

\begin{align} \mathcal{G} \equiv 8 (E_{ab} E^{ab} - B_{ab} B^{ab}) ~, \end{align}

is the Gauss-Bonnet scalar and the coupling function is given by

\begin{align} f(\Psi) \equiv \lambda \Psi + \dfrac{1}{16} \left( \eta \Psi^2 + 2 \zeta \Psi^4 \right) ~, \end{align}

Here the Gauss-Bonnet scalar (in vacuum) is given in terms of the electric ( \( E_{ab} \)) and magnetic ( \( B_{ab} \)) parts of the Weyl scalar.


The documentation for this struct was generated from the following file: