2011/02/17 by Y. M. Cho, Yoonjun Cho, S. H. Oh +5
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Relativity and Gravitational Theory #gr-qc #hep-th
paper · pdf · doi:10.48550/arxiv.1102.3490
arxiv created 2011/02/17 · openalex publication_date 2011/02/17 · arxiv updated 2011/02/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Based on the view that Einstein's theory can be interpreted as a gauge theory of Lorentz group, we decompose the gravitational connection (the gauge potential of Lorentz group) \vGmμ into the restricted connection made of the potential of the maximal Abelian subgroup H of Lorentz group G and the valence connection made of G/H part of the potential which transforms covariantly under Lorentz gauge transformation. With this decomposition we show that the Einstein's theory can be decomposed into the restricted part made of the restricted connection which has the full Lorentz gauge invariance and the valence part made of the valence connection which plays the role of gravitational source of the restricted gravity. We show that there are two different Abelian decomposition of Einstein's theory, the light-like (or null) decomposition and the non light-like (or non-null) decomposition, because Lorentz group has two maximal Abelian subgroups. In this decomposition the role of the metric g_\mn is replaced by a four-index metric tensor \vg_\mn which transforms covariantly under the Lorentz group, and the metric-compatibility condition ∇αg_\mn=0 of the connection is replaced by the gauge and generally covariant condition \mathscr Dμ\vg^\mn=0. The decomposition shows the existence of a restricted theory of gravitation which has the full general invariance but is much simpler and has less physical degrees of freedom than Einstein's theory. Moreover, it tells that the restricted gravity can be written as an Abelian gauge theory, which implies that the graviton can be described by a massless spin-one field.