According to Einstein, the notions of geodesic, parallel transport (affine connection), and curvature of space-time manifold have a pure geometric origin and do not correlate with any electromagnetic concepts. At the same time, curvature is generated by matter which is not affiliated with geometric concepts. For this reason, the fundamental constant c entering the geometric and matter sectors o...

In any quantum theory of gravity we do expect corrections to Einstein gravity to occur. Yet, at fundamental level, it is not apparent what the most relevant corrections are. We argue that the generic curvature square corrections present in lower dimensional actions of various compactified string theories provide a natural passage between the classical and quantum realms of gravity. The Gauss-Bo...

We study the Dirac equation minimally coupled to general relativity using quantum field theory and semiclassical gravity approximation. Previous studies of Einstein-Dirac system did not quantize required multiple independent fields preserve spherical symmetry. canonically a single in static spherically symmetric curved spacetime background. Using approximation, which Einstein equations are sour...

We study inflation driven by the Higgs field in Einstein-Cartan formulation of gravity. In this theory, presence Holst and Nieh-Yan terms with non-minimally coupled to them leads three additional coupling constants. For a broad range parameters, we find that is both possible consistent observations. most cases, spectral index given $n_s=1-2/N_\star$ (with $N_\star$ number e-foldings) whereas te...