Gauge-Invariant Post-Newtonian Perturbations in Symmetric Teleparallel Gravity

We present an extension to the gauge-invariant formulation of parameterized post-Newtonian (PPN) formalism, which allows its application symmetric teleparallel gravity theories. In original formulation, PPN formalism makes use a perturbative expansion tensor fields; however, one fundamental gravitational field variables in theories is flat, torsion-free connection, hence not field. Since connections transform differently from fields under diffeomorphisms, we introduce here adapted notion perturbation for and show how lowest order terms can be expressed common potentials.