PT Journal
AU Barrientos, E
   Lobo, FSN
   Mendoza, S
   Olmo, GJ
   Rubiera-Garcia, D
TI Metric-affine f(R,T) theories of gravity and their applications
SO Physical Review D
JI Phys. Rev. D
PY 2018
BP 104041
EP 10pp
VL 97
IS 10
DI 10.1103/PhysRevD.97.104041
LA English
AB We study f (R, T) theories of gravity, where T is the trace of the energy-momentum tensor T-mu v, with independent metric and affine connection (metric-affine theories). We find that the resulting field equations share a close resemblance with their metric-affine f(R) relatives once an effective energy-momentum tensor is introduced. As a result, the metric field equations are second-order and no new propagating degrees of freedom arise as compared to GR, which contrasts with the metric formulation of these theories, where a dynamical scalar degree of freedom is present. Analogously to its metric counterpart, the field equations impose the nonconservation of the energy-momentum tensor, which implies nongeodesic motion arid consequently leads to the appearance of an extra force. The weak field limit leads to a modified Poisson equation formally identical to that found in Eddington-inspired Born-Infeld gravity. Furthermore, the coupling of these gravity theories to perfect fluids, electromagnetic, and scalar fields, and their potential applications arc discussed.
ER