Four-dimensional (4D) simplicial quantum gravity coupled to both scalar fields (NX) and gauge fields (NA) has been studied using Monte-Carlo simulations. The matter dependence of the string susceptibility exponent γ (4) is estimated. Furthermore, we compare our numerical results with Background-Metric-Independent (BMI) formulation conjectured to describe the quantum field theory of gravity in 4...

In this paper, we demonstrate the feasibility of jointly inverting 4D gravity data collected on the surface and in a borehole setting to characterize fluid contact movement over time. As technology rapidly advances towards a practical borehole gravity meter capable of collecting data in horizontal monitoring wells, the foundations for properly inverting and interpreting these valuable data must...

We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4 + d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this e...

A thorough numerical examination for the field theory of 4D quantum gravity (QG) with a special emphasis on the conformal mode dependence has been studied. More clearly than before, we obtain the string susceptibility exponent of the partition function by using the Grand-Canonical Monte-Carlo method. Taking thorough care of the update method, the simulation is made for 4D Euclidean simplicial m...

The occurence of 5d de Sitter space with 4d de Sitter brane is discussed on classical and quantum level. It is shown that quantum effects maybe produced by dual CFT living on the brane. Moreover, gravity trapping on the brane is proved via the presentation of 5d dS gravity as 4d gravity coupled with gauge theory. This supports the dS/CFT correspondence. Some open questions in 5d dS/4d CFT corre...

We revisit the 5D gravity model by Dvali, Gabadadze, and Porrati (DGP). In the model it was shown that even in 5D non-compact Minkowski space, the Newtonian gravity can emerge on a brane at short distance by introducing a brane-localized 4D Ricci scalar δ(z)M2 4 R̄4 in the action. Based on this idea, we construct simple setups in which graviton standing waves can arise, and we introduce a z deri...

We perform the spherical symmetric dimensional reduction 4d → 2d of heterotic string theory. We find a class of two-dimensional (2d) dilaton gravity models that gives a general description of the near-horizon, near-extremal behavior of four-dimensional (4d) heterotic string black holes. We show that the duality group of the 4d theory is realized in two dimensions in terms of Weyl transformation...

An alternative to usual dimensional reduction for gravity is analyzed, in the vielbein-spin connection formulation. Usual 4d Einstein gravity plus a topological term (the ”Born-Infeld” Lagrangian for gravity), is shown to be obtained by a generalized dimensional reduction from 5d Chern-Simons gravity. Chern-Simons gravity in d=2n+1 is dimensionally reduced to CS gravity in d=2n-1 via a mechanis...

We perform the spherical symmetric dimensional reduction 4d → 2d of heterotic string theory. We find a class of two-dimensional (2d) dilaton gravity models that gives a general description of the near-horizon, near-extremal behavior of four-dimensional (4d) heterotic string black holes. We show that the duality group of the 4d theory is realized in two dimensions in terms of Weyl transformation...

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 a vector field (NV = 1) is smooth compared with pure gravity(NV = 0). The node susceptibility (χ) is studied by the finite size scaling method. At the critical point, the node distribution has a sharp peak in...