Differences between scalar field and scalar density solutions
We explore differences between scalar field, and scalar density solutions by using Robertson-Walker (RW) metric, and also a non-relativistic Hamiltonian is derived for a scalar density field in the post-Newtonian approximation. The results are compared with those of scalar field. The expanding universe in RW metric, and post-Newtonian solution of Klein-Gordon equation are separately discussed.
gr-qc↗