scholarly journals Gauge Theories: From Kaluza–Klein to noncommutative gravity theories

Symmetry ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 856
Author(s):  
George Manolakos ◽  
Pantelis Manousselis ◽  
George Zoupanos
Keyword(s):  
Dimensional Reduction ◽  
Particle Physics ◽  
Extra Dimensions ◽  
Gauge Theories ◽  
Dimensional Theory ◽  
Higher Dimensional ◽  
Coset Spaces ◽  
Gravity Theories ◽  
Physics Model ◽  
Kaluza Klein

First, the Coset Space Dimensional Reduction scheme and the best particle physics model so far resulting from it are reviewed. Then, a higher-dimensional theory in which the extra dimensions are fuzzy coset spaces is described and a dimensional reduction to four-dimensional theory is performed. Afterwards, another scheme including fuzzy extra dimensions is presented, but this time the starting theory is four-dimensional while the fuzzy extra dimensions are generated dynamically. The resulting theory and its particle content is discussed. Besides the particle physics models discussed above, gravity theories as gauge theories are reviewed and then, the whole methodology is modified in the case that the background spacetimes are noncommutative. For this reason, specific covariant fuzzy spaces are introduced and, eventually, the program is written for both the 3-d and 4-d cases.

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.

GRAVITATIONAL BAG EFFECTS ON KALUZA KLEIN AND STRING EXCITATIONS

1989 ◽  
Vol 04 (19) ◽  
pp. 5119-5131 ◽  
Author(s):  
E. I. GUENDELMAN
Keyword(s):  
Extra Dimensions ◽  
Blow Up ◽  
Point Of View ◽  
Spherically Symmetric ◽  
Massive String ◽  
Free Objects ◽  
Higher Dimensional ◽  
Central Regions ◽  
The Masses ◽  
Kaluza Klein

Gravitational Bags are spherically symmetric solutions of higher-dimensional Kaluza Klein (K – K) theories, where the compact dimensions become very large near the center of the geometry, although they are small elsewhere. The K – K excitations therefore become very light when located near the center of this geometry and this appears to affect drastically the naive tower of the masses spectrum of K – K theories. In the context of string theories, string excitations can be enclosed by Gravitational Bags, making them not only lighter, but also localized, as observed by somebody, that does not probe the central regions. Strings, however, can still have divergent sizes, as quantum mechanics seems to demand, since the extra dimensions blow up at the center of the geometry. From a projected 4-D point of view, very massive string bits may lie inside their Schwarzschild radii, as pointed out by Casher, Gravitational Bags however are horizon free objects, so no conflict with macroscopic causality arises if the string excitations are enclosed by Gravitational Bags.

scholarly journals Geography of fields in extra dimensions: String theory lessons for particle physics

2015 ◽  
Vol 30 (10) ◽  
pp. 1530008 ◽  
Author(s):  
Hans Peter Nilles ◽  
Patrick K. S. Vaudrevange
Keyword(s):  
String Theory ◽  
Particle Physics ◽  
Extra Dimensions ◽  
Model Building ◽  
Unified Theory ◽  
Fundamental Interactions ◽  
Spatial Dimensions ◽  
Physics Model ◽  
String Theories

String theoretical ideas might be relevant for particle physics model building. Ideally one would hope to find a unified theory of all fundamental interactions. There are only a few consistent string theories in D = 10 or 11 spacetime dimensions, but a huge landscape in D = 4. We have to explore this landscape to identify models that describe the known phenomena of particle physics. Properties of compactified six spatial dimensions are crucial in that respect. We postulate some useful rules to investigate this landscape and construct realistic models. We identify common properties of the successful models and formulate lessons for further model building.

scholarly journals Cosmic cloaking of rich extra dimensions

2021 ◽  
Author(s):  
Aghil Alaee ◽  
Marcus Khuri ◽  
Hari Kunduri
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Dimensional Theory ◽  
Hoop Conjecture ◽  
Significant Size ◽  
The Universe ◽  
Lower Dimensional ◽  
Kaluza Klein

We present arguments that show why it is difficult to see rich extra dimensions in the universe. Conditions are found where significant size and variation of the extra dimensions in a Kaluza–Klein compactification lead to a black hole in the lower-dimensional theory. The idea is based on the hoop conjecture concerning black hole existence, as well as on the observation that dimensional reduction on macroscopically large, twisted, or highly dynamical extra dimensions contributes positively to the energy density in the lower-dimensional theory and can induce gravitational collapse. A threshold for the size is postulated on the order of [Formula: see text][Formula: see text]m, whereby extra dimensions of length above this level must lie inside black holes, thus cloaking them from the view of outside observers. The threshold depends on the size of the universe, leading to speculation that in the early stages of evolution truly macroscopic and large extra dimensions would have been visible.

scholarly journals Higher-Dimensional Unification with continuous and fuzzy coset spaces as extra dimensions

2015 ◽  
Vol 63 (7-8) ◽  
pp. 442-467 ◽  
Author(s):  
D. Gavriil ◽  
G. Manolakos ◽  
G. Orfanidis ◽  
G. Zoupanos
Keyword(s):  
Extra Dimensions ◽  
Higher Dimensional ◽  
Coset Spaces

scholarly journals LABORATORY LIMITS ON THEORIES WITH STERILE NEUTRINOS IN THE BULK

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 931-933 ◽  
Author(s):  
ARA IOANNISIAN ◽  
APOSTOLOS PILAFTSIS
Keyword(s):  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Effective Theory ◽  
Sterile Neutrinos ◽  
Order Unity ◽  
Yukawa Couplings ◽  
Original Order ◽  
Higher Dimensional ◽  
Decoupling Effect ◽  
Kaluza Klein

We discuss the phenomenological consequences of theories which describe sterile neutrinos in large extra dimensions, in the so-called bulk. We briefly outline how the cumulative non-decoupling effect due to the tower of Kaluza-Klein singlet neutrinos may equivalently be described by a higher-dimensional effective theory with original order-unity Yukawa couplings. Based on this cumulative phenomenon, we obtain strong constraints on the fundamental quantum gravity scale and/or on the higher-dimensional Yukawa couplings.

SIX-DIMENSIONAL BRANEWORLD COSMOLOGY

2011 ◽  
Vol 01 ◽  
pp. 189-194 ◽  
Author(s):  
MASATO MINAMITSUJI
Keyword(s):  
Magnetic Flux ◽  
Power Law ◽  
Dimensional Reduction ◽  
Extra Dimensions ◽  
Inflationary Universe ◽  
Maxwell Theory ◽  
Braneworld Cosmology ◽  
Codimension Two ◽  
Higher Dimensional ◽  
Cosmological Solutions

We derive the brane cosmological solutions in the six-dimensional Einstein-Maxwell-dilaton theory, via dimensional reduction from the higher-dimensional Einstein-Maxwell theory. Two extra dimensions are compactified by a magnetic flux and two codimension-two branes are located at the boundaries. All the cosmological solutions approach an attractor in the later times. The attractor represents a simple power-law inflationary Universe whose power is simply given by the dilatonic coupling in the theory. Then, we discuss the properties of our solutions and deduce the cosmological implications.

HIGHER-DIMENSIONAL OPERATORS TO THE RESCUE OF MINIMAL SU(5)

1993 ◽  
Vol 08 (16) ◽  
pp. 1487-1494 ◽  
Author(s):  
BISWAJOY BRAHMACHARI ◽  
P.K. PATRA ◽  
UTPAL SARKAR ◽  
K. SRIDHAR
Keyword(s):  
Quantum Gravity ◽  
Extra Dimensions ◽  
Large Range ◽  
Spontaneous Compactification ◽  
Higher Dimensional ◽  
Gravity Effects ◽  
Proton Lifetime ◽  
Range Of Values ◽  
Kaluza Klein

We consider the modification of the minimal SU(5) Lagrangian due to higher-dimensional operators, arising from quantum gravity effects or from spontaneous compactification of extra dimensions in Kaluza-Klein type theories. Due to these operators the SU (3)c, SU (2)L and U (1)Y couplings do not meet at all at the unification scale, MU, and the magnitudes of the mismatch are directly related to the couplings of the higher-dimensional operators. In particular, we consider five- and six-dimensional operators and show that a large range of values of couplings of these operators are compatible with the latest values of sin 2 θW and as derived from LEP, and also with the experimental constraints on MU coming from proton lifetime.

scholarly journals Kaluza–Klein reduction and Bergmann–Wagoner bi-scalar general action of scalar–tensor gravity

2015 ◽  
Vol 12 (10) ◽  
pp. 1550106 ◽  
Author(s):  
Kazuharu Bamba ◽  
Davood Momeni ◽  
Ratbay Myrzakulov
Keyword(s):  
Dimensional Reduction ◽  
Dimensional Space ◽  
Space Time ◽  
De Sitter ◽  
Higher Dimensional Space Time ◽  
Higher Dimensional ◽  
Dimensional Space Time ◽  
General Action ◽  
The Stability ◽  
Kaluza Klein

We examine the Kaluza–Klein (KK) dimensional reduction from higher dimensional space-time and the properties of the resultant Bergmann–Wagoner general action of scalar–tensor theories. With the analysis of the perturbations, we also investigate the stability of the anti-de Sitter (AdS) space-time in the (D ∈ 𝒩)-dimensional Einstein gravity with the negative cosmological constant. Furthermore, we derive the conditions for the dimensional reduction to successfully be executed and present the KK compactification mechanism.

Sign in / Sign up

Export Citation Format

Share Document