Non-trivial frames for f ( T ) theories of gravity and beyond

摘要

Some conceptual issues concerningf(T)theories – a family of modified gravity theories based on absolute parallelism – are analyzed. Due to the lack of local Lorentz invariance, the autoparallel frames satisfying the field equations are evasive to ana prioriphysical understanding. We exemplify this point by working out the vierbein (tetrad) fields for closed and open Friedmann–Robertson–Walker cosmologies.