Gravitational waves in modified teleparallel theories of gravity

Teleparallel theory of gravity and its modifications have been studied extensively in literature. However, gravitational waves has not been studied enough in the framework of teleparallelism. In the present study, we discuss gravitational waves in general theories of teleparallel gravity containing the torsion scalar T, the boundary term B and a scalar field phi. The goal is to classify possible new polarizations generalizing results presented in Bamba et al. (Phys Lett B 727: 194-198, arXiv: 1309.2698, 2013). We show that, if the boundary term is minimally coupled to the torsion scalar and the scalar field, gravitational waves have the same polarization modes of General Relativity.