Poincare gauge theory cosmology
For the quadratic Poincare gauge theory of gravity (PG) we consider the FLRW cosmologies using an isotropic Bianchi representation. This study begins the investigation of the most general PG cosmology: all the possible even and odd parity terms of the quadratic PG with their respective scalar and pseudoscalar parameters are allowed with no a priori restrictions on their values. Cosmologically this brings in some novel interaction terms controlled by one new parameter. With the aid of a manifestly homogeneous and isotropic representation, an effective Lagrangian gives the second order dynamical equations for the gauge potentials. An equivalent set of first order equations for the observables is presented. The generic behavior of physical solutions is discussed and illustrated using numerical simulations.
Reference: F-H Ho, H Chen, JM Nester & H-J Yo: Chinese J Phys 53 (2015) 110109.