Cosmic acceleration via derivative matter couplings
School of Physics, Damghan University, 41167-36716, Damghan, Iran
Accepted: 12 June 2020
Published online: 19 June 2020
We consider a modification of gravity via derivative matter couplings. We will consider a healthy higher-order Lagrangian for a scalar field which is constructed from the matter Lagrangian. Generally, the energy–momentum tensor is not conserved, leading to the fifth force. We will however show that the fifth force vanishes on top of the FRW background. Cosmological implications and the energy conditions will be considered in detail. Also we will perform the dynamical system analysis of the model and show that there exists a meta stable de Sitter fixed point which can be seen as a final stage of the universe evolution.
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