Scalar field equation in the form of the Current, J^\mu

[Purnendu Karmakar]

Dear friends, 

I am interested in writing the scalar field equation of motion (EOM) in the form of the current, J^\mu, i.e., \nabla_\mu (J^\mu). In xAct, after expanding the perturbation, and vary the perturbation, I can write the EOM in the expanded form, i.e., explicit form after nabla acts on J^\mu. 

I would appreciate if somebody kindly helps me to write scalar field equation in the form of the derivative of current.

Thanks and regards, Purnendu