Soliton transformations for axially symmetric higher‐dimensional gravity. I. Generalized Neugebauer–Kramer transformations

1987 ◽  
Vol 28 (4) ◽  
pp. 893-900 ◽  
Author(s):  
S.‐C. Lee
Keyword(s):  
Axially Symmetric ◽  
Higher Dimensional ◽  
Dimensional Gravity

scholarly journals Unitarity in KK-graviton production, a case study in warped extra-dimensions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. de Giorgi ◽  
S. Vogl
Keyword(s):  
Extra Dimensions ◽  
Sum Rules ◽  
Effective Theory ◽  
Higher Dimensional ◽  
Massive Spin ◽  
The Matrix ◽  
Dimensional Gravity ◽  
Warped Extra Dimensions ◽  
Kaluza Klein

Abstract The Kaluza-Klein (KK) decomposition of higher-dimensional gravity gives rise to a tower of KK-gravitons in the effective four-dimensional (4D) theory. Such massive spin-2 fields are known to be connected with unitarity issues and easily lead to a breakdown of the effective theory well below the naive scale of the interaction. However, the breakdown of the effective 4D theory is expected to be controlled by the parameters of the 5D theory. Working in a simplified Randall-Sundrum model we study the matrix elements for matter annihilations into massive gravitons. We find that truncating the KK-tower leads to an early breakdown of perturbative unitarity. However, by considering the full tower we obtain a set of sum rules for the couplings between the different KK-fields that restore unitarity up to the scale of the 5D theory. We prove analytically that these are fulfilled in the model under consideration and present numerical tests of their convergence. This work complements earlier studies that focused on graviton self-interactions and yields additional sum rules that are required if matter fields are incorporated into warped extra-dimensions.

Dark matter self-interactions from higher dimensional gravity

2006 ◽  
Vol 73 (12) ◽  
Author(s):  
Nicolas Chatillon ◽  
Cosmin Macesanu ◽  
Aleksandr Pinzul ◽  
Mark Trodden
Keyword(s):  
Dark Matter ◽  
Higher Dimensional ◽  
Dimensional Gravity

scholarly journals Axisymmetric three-dimensional gravity currents generated by lock exchange

2018 ◽  
Vol 851 ◽  
pp. 507-544 ◽  
Author(s):  
Roberto Inghilesi ◽  
Claudia Adduce ◽  
Valentina Lombardi ◽  
Federico Roman ◽  
Vincenzo Armenio
Keyword(s):  
Froude Number ◽  
Flow Rate ◽  
Rapid Development ◽  
Three Dimensional ◽  
Gravity Currents ◽  
Constant Flow ◽  
Axially Symmetric ◽  
Grashof Number ◽  
Constant Flow Rate ◽  
Dimensional Gravity

Unconfined three-dimensional gravity currents generated by lock exchange using a small dividing gate in a sufficiently large tank are investigated by means of large eddy simulations under the Boussinesq approximation, with Grashof numbers varying over five orders of magnitudes. The study shows that, after an initial transient, the flow can be separated into an axisymmetric expansion and a globally translating motion. In particular, the circular frontline spreads like a constant-flow-rate, axially symmetric gravity current about a virtual source translating along the symmetry axis. The flow is characterised by the presence of lobe and cleft instabilities and hydrodynamic shocks. Depending on the Grashof number, the shocks can either be isolated or produced continuously. In the latter case a typical ring structure is visible in the density and velocity fields. The analysis of the frontal spreading of the axisymmetric part of the current indicates the presence of three regimes, namely, a slumping phase, an inertial–buoyancy equilibrium regime and a viscous–buoyancy equilibrium regime. The viscous–buoyancy phase is in good agreement with the model of Huppert (J. Fluid Mech., vol. 121, 1982, pp. 43–58), while the inertial phase is consistent with the experiments of Britter (Atmos. Environ., vol. 13, 1979, pp. 1241–1247), conducted for purely axially symmetric, constant inflow, gravity currents. The adoption of the slumping model of Huppert & Simpson (J. Fluid Mech., vol. 99 (04), 1980, pp. 785–799), which is here extended to the case of constant-flow-rate cylindrical currents, allows reconciling of the different theories about the initial radial spreading in the context of different asymptotic regimes. As expected, the slumping phase is governed by the Froude number at the lock’s gate, whereas the transition to the viscous phase depends on both the Froude number at the gate and the Grashof number. The identification of the inertial–buoyancy regime in the presence of hydrodynamic shocks for this class of flows is important, due to the lack of analytical solutions for the similarity problem in the framework of shallow water theory. This fact has considerably slowed the research on variable-flow-rate axisymmetric gravity currents, as opposed to the rapid development of the knowledge about cylindrical constant-volume and planar gravity currents, despite their own environmental relevance.

scholarly journals HIGHER GAUGE THEORY AND GRAVITY IN 2+1 DIMENSIONS

2007 ◽  
Vol 22 (28) ◽  
pp. 5155-5172 ◽  
Author(s):  
R. B. MANN ◽  
E. M. POPESCU
Keyword(s):  
Gauge Theory ◽  
Two Dimensional ◽  
Yang Mills ◽  
Higher Dimensional ◽  
Present Context ◽  
Dimensional Gravity ◽  
Wide Perspective ◽  
Higher Gauge Theory ◽  
Matter Fields ◽  
New Framework

Non-Abelian higher gauge theory has recently emerged as a generalization of standard gauge theory to higher-dimensional (two-dimensional in the present context) connection forms, and as such, it has been successfully applied to the non-Abelian generalizations of the Yang–Mills theory and 2-form electrodynamics. (2+1)-dimensional gravity, on the other hand, has been a fertile testing ground for many concepts related to classical and quantum gravity, and it is therefore only natural to investigate whether we can find an application of higher gauge theory in this latter context. In the present paper we investigate the possibility of applying the formalism of higher gauge theory to gravity in 2+1 dimensions, and we show that a nontrivial model of (2+1)-dimensional gravity coupled to scalar and tensorial matter fields — the ΣΦEA model — can be formulated as a higher gauge theory (as well as a standard gauge theory). Since the model has a very rich structure — it admits as solutions black-hole BTZ-like geometries, particle-like geometries as well as Robertson–Friedman–Walker cosmological-like expanding geometries — this opens a wide perspective for higher gauge theory to be tested and understood in a relevant gravitational context. Additionally, it offers the possibility of studying gravity in 2+1 dimensions coupled to matter in an entirely new framework.

Inflation with higher dimensional gravity

1985 ◽  
Vol 152 (1-2) ◽  
pp. 51-55 ◽  
Author(s):  
Q. Shafi ◽  
C. Wetterich
Keyword(s):  
Higher Dimensional ◽  
Dimensional Gravity

scholarly journals Non-Static Local String in Higher-Dimensional Gravity

2005 ◽  
Vol 44 (9) ◽  
pp. 1413-1418
Author(s):  
F. Rahaman ◽  
B. C. Bhui ◽  
M. Kalam
Keyword(s):  
Higher Dimensional ◽  
Dimensional Gravity
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