2015/12/30 by Laur Järv, Piret Kuusk, Jarv, Laur +5
Physics and Astronomy · Earth and Planetary Sciences · #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.1512.09166
We give a brief summary of the formalism of invariants in general\nscalar-tensor and multiscalar-tensor gravities without derivative couplings. By\nrescaling of the metric and reparametrization of the scalar fields, the theory\ncan be presented in different conformal frames and parametrizations. Due to\nthis freedom in transformations, the scalar fields themselves do not carry\nindependent physical meaning (in a generic parametrization). However, there are\nfunctions of the scalar fields and their derivatives which remain invariant\nunder the transformations, providing a set of physical variables for the\ntheory. We indicate how to construct such invariants and show how the\nobservables like parametrized post-Newtonian parameters and characteristics of\nFriedmann-Lemaitre-Robertson-Walker cosmology can be neatly expressed in terms\nof the invariants.\n