Primordial Fluctuations within Teleparallelism

We study the cosmological perturbations for the possible inflation scenario in the teleparallel equivalence of general relativity specified with parallelizable topological conditions. By acquiring the identical physical observables to general relativity under the teleparallel formalism, we perform a 3+1 decomposition of the vierbein field, which can be interpreted as the time gauge fixing between coordinate and tangent frames. We also extend our discussion to the higher-order action, $f(T)$ gravity.