The VDF potential is a four-vector of the form

\[ A^{\mu} = \sum_{i=1}^N C_i \left(\frac{\rho}{\rho_0}\right)^{b_i - 2} \frac{j^{\mu}}{\rho_0} \,, \]

where \(j^{\mu}\) is baryon 4-current, \(\rho\) is baryon density in the local Eckart rest frame, and \(\rho_0\) is the saturation density. The parameters of the potential, the coefficients \(C_i\) and the powers \(b_i\), are fitted to reproduce a chosen set of properties of dense nuclear matter, and in particular these may include describing two first order phase transitions: the well-known phase transition in ordinary nuclear matter, and a transition at high baryon densities meant to model a possible QCD phase transition (a "QGP-like" phase transition); see Sorensen:2020ygf [54] for details and example parameter sets for the case \(N=4\). The user can decide how many terms \(N\) should enter the potential by populating the coefficients and powers vectors in the config file with a chosen number of entries. The number of coefficients must match the number of powers.

The potential parameters must be specified in the VDF subsection of the Potentials one.

Coeffs — list of doubles, required

Parameters \(C_i\) of the VDF potential in MeV.

Powers — double, required

Parameters \(b_i\) of the VDF potential.

Warning: You need to provide as many entries for Powers as provided for Coeffs.

Sat_rhoB — double, required

The saturation density of nuclear matter in 1/fm³.