A. Al-Badawi

Is Li Time-Machine Metric Valid in f(R,ℒm,Φ,gμν∇μΦ∇νΦ) Gravity?

A modified gravitational model whose action is given by an arbitrary function of the Ricci scalar, the matter Lagrangian density, a scalar field, and its kinetic term is investigated as an extension of the gravitational sector with one additional dynamical degree of freedom. Within this framework, the causal structure...