Large Scale Lorentz Violation as the Possible Origin of Dark Energy.

The accelerating expansion of universe can be described by the non-zero cosmological constant or the dark energy. However, the origin of the dark energy remains a mystery of modern physics. The local Lorentz invariance is the most exact symmetry of the Nature on the one hand, but all quantum gravity theories predict Lorentz violation on the other hand. The local Lorentz violation induced by the quantum gravity at the very early universe may be transformed into large scale by inflation. Combining the low-$l$ anomalies of the CMB spectrum, we propose that the local Lorentz invariance may be broken at the large scale. We construct the effective gravity at the cosmic scale with a local $SO(3)$ symmetry. The theory exhibits non-trivial contortion distribution even with scalar matter source. The FRW like solution of the theory is analyzed and the contortion distribution contributes a dark energy like effect which is responsible for the accelerating expansion of the universe.