jesterTOV.tov.scalar_tensor.ScalarTensorTOVSolver

jesterTOV.tov.scalar_tensor.ScalarTensorTOVSolver#

class ScalarTensorTOVSolver[source]#

Bases: TOVSolverBase

Scalar-tensor theory TOV solver.

Solves modified TOV equations that include scalar field coupling. The solution requires iterative solving to match boundary conditions at the star surface and spatial infinity.

Implements the scalar-tensor TOV equations with tidal deformability following Creci et al. (2023) Phys.Rev.D 111 (2025) 8, 089901 (erratum).

Parameters:

  • beta_ST (float, optional) – Scalar-tensor coupling parameter \(\\beta_{\\mathrm{ST}}\).

  • phi_inf_tgt (float, optional) – Target asymptotic value of the scalar field at infinity.

  • phi_c (float, optional) – Central value of the scalar field.

Notes

The solver computes both the stellar structure and tidal deformabilities (tensor \(\\Lambda_T\), scalar \(\\Lambda_S\), and mixed \(\\Lambda_{\\mathrm{ST}}\)) using matched asymptotic expansions.

__init__()#

Methods

__init__()

construct_family(eos_data, ndat, min_nsat, ...)

Construct M-R-Λ curves by solving for multiple central pressures.

fetch_params(params)

Extract solver-specific parameters from the combined EOS+TOV parameter dict.

get_required_parameters()

Return additional parameters required by scalar-tensor TOV solver.

solve(eos_data, pc, tov_params)

Solve scalar-tensor TOV equations for given EOS and central pressure.
get_required_parameters()[source]#

Return additional parameters required by scalar-tensor TOV solver.

Return type:

list[str]

Returns:

list[str] – List of parameter names: ["beta_ST", "phi_inf_tgt", "phi_c"].

Notes

These parameters correspond to: - beta_ST: Scalar-tensor coupling constant. - phi_inf_tgt: Target asymptotic scalar field value at infinity. - phi_c: Central scalar field value.

solve(eos_data, pc, tov_params)[source]#

Solve scalar-tensor TOV equations for given EOS and central pressure.

Parameters:

  • eos_data (EOSData) – Equation of state data containing pressure, enthalpy, energy density, and logarithmic derivatives.

  • pc (float) – Central pressure (geometric units).

  • tov_params (dict[str, float]) – Scalar-tensor theory parameters: beta_ST is the coupling constant (dimensionless), phi_c is the central scalar field value (dimensionless), and phi_inf_tgt is the target asymptotic scalar field value at infinity (dimensionless).

Return type:

TOVSolution

Returns:

TOVSolution – Solution containing mass, radius, and Love number k2 in Jordan frame.

Raises:

ValueError – If iteration fails to converge.

Notes

The solver uses iterative matching to find the central scalar field value that yields the desired asymptotic value at infinity. Tidal deformabilities are computed using two particular interior solutions combined with exterior basis functions.

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