A bstract We compute the leading order non-Gaussianity, i.e., bispectrum, of tensor perturbation in general ? -vacuum on de Sitter space relativity. In addition to well-known Bunch-Davies (BD) vacuum, there exits an infinite number invariant vacua represented by a real parameter and phase ? , with = 0 being BD vacuum. They are called -vacua. standard slow-roll inflation, as invariance no longer...

We study the properties of the poles of the resummed graviton propagator obtained by resumming bubble matter diagrams which correct the classical graviton propagator. These poles have been previously interpreted as black holes precursors. Here, we show using the horizon wavefunction formalism that these poles indeed have properties which make them compatible with being black hole precursors. In...

We present an extension of the Randall–Sundrum model in which, due to spontaneous Lorentz symmetry breaking, graviton mixes with bulk vector fields and becomes quasilocalized. The masses of KK modes comprising the four-dimensional graviton are naturally exponentially small. This allows to push the Lorentz breaking scale to as high as a few tenth of the Planck mass. The model does not contain gh...

We employ the LSZ reduction formula for Matrix Theory introduced in our earlier work to compute the t-pole S-matrix for three form–three form scattering. The result agrees completely with tree level D = 11 SUGRA. Taken together with previous results on graviton-graviton scattering this shows that Matrix Theory indeed reproduces the bosonic sector of the D = 11 SUGRA action including the Chern-S...