Parameter Constrain of Nonminimal Derivative Coupling of Scalar Field Using Strong Energy Condition

Abstract

The study aims to determine the constrain of the coupling parameter/xi of nonminimal derivative coupling theory (NMDC) of scalar field. The calculation of the parameter was build from the strong energy conditions combined to modified Einstein theory(i.e. the scalar filed act as the external source of gravity beside the ideal fluid). The violation of strong energy condition (SEC) indicate the atrracting gravity phenomenon. Then one can expecting two equations that consist of of energy density ρ and the momentum p, then one defined the deacceleration q to these equation. The present value of cosmological constant such as Hubble constant H, q, and scale factor a need to be put into the equations to determine the boundaries of the strong energ. The results show the coupling parameter must be ξ ≥ 1.2 × 1034 s2 for the SEC to be valid in the theory.