My Lagrangian comes out in this form when I impose spherical symmetry:
$$ φ''(ρ)+{3\overρ} φ'(ρ)+{4μ^4\over M^2} φ(ρ)-{4μ^4\over M^4} φ^{3}(ρ)-{μ^4\over2M} ϵ=0 $$
The following boundary conditions apply: $ φ'(0)=0 $,$ φ'(∞)=0$, $ φ(0)=-φ_0$ And I've found that the fourth boundary value is:
$ φ(∞)={M(2^{1\over3}(\sqrt(81 \epsilon^2-768)-9 \epsilon)^{2\over3}+8 (3)^{1\over3})\over2 (6)^{2\over3} (\sqrt(81 \epsilon^2-768)-9 \epsilon)^{1\over3}}=φ_1$
The boundary on $ \phi(0) $ is a parameter I will find through variation according to specifics of my research, so for now I have simply left it as $\phi_0$. Assume everything is positive except the function, which can have negative values (thus the - sign in $φ(0)$). Also, $\rho$ is the only variable, so ODE.
I want to model the scalar field, but am having trouble solving for it. I know there is no analytic solution and I can easily redefine $φ'(ρ)=g(ρ)$ to get $2$ equations, but I am stumped about what numerical method to use to solve this monster.
How should I go about solving this?
Edit
Also, I wouldn't say no to tips on making this question more "answer-friendly".
Edit 2
I've found the following equation fits the boundary conditions, so that might be something to start with even if it doesn't fit the ODE:
$$\Phi(\rho)=\phi_1 e^{-\rho}+(2\phi_1+\phi_0)tanh({\phi_1 \rho\over 2\phi_1+\phi_0})-\phi_1-\phi_0$$