We revisit the 5D gravity model by Dvali, Gabadadze, and Porrati (DGP). Within their framework it was shown that even in 5D non-compact Minkowski space (x, z), the Newtonian gravity can emerge on a brane at short distances by introducing a brane-localized 4D Einstein-Hilbert term δ(z)M2 4 √ |ḡ4|R̄4 in the action. Based on this idea, we construct simple setups in which graviton standing waves can...

The phase transition of 4D simplicial quantum gravity coupled to U (1) gauge fields is studied using Monte-Carlo simulations. The phase transition of the dynamical triangulation model with vector field (NV = 1) is smooth as compared with the pure gravity(NV = 0). The node susceptibility (χ) is studied in the finite size scaling method. At the critical point, the node distribution has a sharp pe...

There are a number of ongoing developments in the 4D gravity method for time-lapse production and sequestration problems. Complex model construction is an essential component for meaningful feasibility studies and data interpretation in 4D. In the case of oil reservoirs, for example, the 4D gravity method must deal with very small density contrasts at depth, and overly simplistic model represen...

We show that a self-tuning mechanism of the cosmological constant could work in 5D non-compact space with Z 2 symmetry with scalar kinetic energy term. The standard model matter fields live only on the 4 dimensional (4D) brane. The change of vacuum energy on the brane (brane cosmological constant) by, for instance, electroweak and QCD phase transitions, just gives rise to dynamical shifts of th...

Dynamical generation of 4d gauge theories and gravity at low energy from the 3d ones at high energy is studied, based on the fermion condensation mechanism recently proposed by Arkani-Hamed, Cohen and Georgi. For gravity, 4d Einstein gravity is generated from the multiple copy of the 3d ones, by referring to the two form gravity. Since the 3d Einstein action without matter coupling is topologic...

We reformulate the scattering amplitudes of 4D flat space gauge theory and gravity in the language of a 2D CFT on the celestial sphere. The resulting CFT structure exhibits an OPE constructed from 4D collinear singularities, as well as infinite-dimensional Kac-Moody and Virasoro algebras encoding the asymptotic symmetries of 4D flat space. We derive these results by recasting 4D dynamics in ter...

It is shown how w∞, w1+∞ Gauge Field Theory actions in 2D emerge directly from 4D Gravity. Strings and Membranes actions in 2D and 3D originate as well from 4D Einstein Gravity after recurring to the nonlinear connection formalism of Lagrange-Finsler and Hamilton-Cartan spaces. Quantum Gravity in 3D can be described by a W∞ Matrix Model in D = 1 that can be solved exactly via the Collective Fie...

We study conformal theories of gravity, i.e. those whose action is invariant under the local transformation gμν → ω(x)gμν . As is well known, in order to obtain Einstein gravity in 4D it is necessary to introduce a scalar compensator with a VEV that spontaneously breaks the conformal invariance and generates the Planck mass. We show that the compactification of extra dimensions in a higher dime...

Higher order renormalization in 4D quantum gravity is carried out using dimensional regularization with great care concerning the conformal-mode dependence. In this regularization, resummation can be automatically performed without making any assumption, like done by David-Distler-Kawai. In this paper we consider a model of 4D quantum gravity coupled to QED. The renormalizability is directly ch...