Higher-dimensional string theory in Lyra geometry

Pramana ◽  
2003 ◽  
Vol 60 (3) ◽  
pp. 453-459 ◽  
Author(s):  
F. Rahaman ◽  
S. Chakraborty ◽  
S. Das ◽  
M. Hossain ◽  
J. Bera
Keyword(s):  
String Theory ◽  
Lyra Geometry ◽  
Higher Dimensional

scholarly journals GRAVITY-WAVE DETECTORS AS PROBES OF EXTRA DIMENSIONS

2005 ◽  
Vol 14 (12) ◽  
pp. 2347-2353 ◽  
Author(s):  
CHRIS CLARKSON ◽  
ROY MAARTENS
Keyword(s):  
Black Holes ◽  
String Theory ◽  
Gravity Wave ◽  
Gravity Waves ◽  
Extra Dimensions ◽  
State Of The Art ◽  
Three Dimensional ◽  
Observable Universe ◽  
Dimensional Spacetime ◽  
Higher Dimensional

If string theory is correct, then our observable universe may be a three-dimensional "brane" embedded in a higher-dimensional spacetime. This theoretical scenario should be tested via the state-of-the-art in gravitational experiments — the current and upcoming gravity-wave detectors. Indeed, the existence of extra dimensions leads to oscillations that leave a spectroscopic signature in the gravity-wave signal from black holes. The detectors that have been designed to confirm Einstein's prediction of gravity waves, can in principle also provide tests and constraints on string theory.

HIGHER DIMENSIONAL COSMOLOGY WITH STRING VACUUM ENERGY

1987 ◽  
Vol 02 (05) ◽  
pp. 299-306 ◽  
Author(s):  
H. NISHIMURA ◽  
M. TABUSE
Keyword(s):  
String Theory ◽  
Vacuum Energy ◽  
Bosonic String ◽  
Extra Space ◽  
Higher Dimensional Cosmology ◽  
Higher Dimensional ◽  
Bosonic String Theory ◽  
The One ◽  
Closed Bosonic String

We consider higher dimensional cosmology based on the closed bosonic string theory with the one-loop vacuum energy. It is concluded that the winding-effect of strings around tori has a chance to prevent the extra space from expanding, even though the curvature of torus is zero.

HIGHER DIMENSIONAL COSMOLOGICAL MODEL IN LYRA GEOMETRY: REVISITED

2003 ◽  
Vol 12 (05) ◽  
pp. 853-860 ◽  
Author(s):  
G. P. SINGH ◽  
S. KOTAMBKAR ◽  
ANIRUDH PRADHAN
Keyword(s):  
Cosmological Model ◽  
Power Law ◽  
Bulk Viscosity ◽  
Research Work ◽  
Lyra Geometry ◽  
Universe Model ◽  
Higher Dimensional ◽  
Empty Universe ◽  
Kaluza Klein

In this paper we have revisited the research work of Rahman and Bera22on Kaluza–Klein cosmological model within the framework of Lyra Geometry. It has been shown that the empty universe model yields a power law relation without any assumption. The role of bulk viscosity on five-dimensional cosmological model is discussed. The physical behaviour of the models is examined in all cases.

Higher dimensional inhomogeneous cosmological models in Lyra geometry

2003 ◽  
Vol 288 (4) ◽  
pp. 483-491 ◽  
Author(s):  
F. Rahaman ◽  
S. Chakraborty ◽  
S. Das ◽  
R. Mukherjee ◽  
M. Hossain ◽  
...  
Keyword(s):  
Lyra Geometry ◽  
Cosmological Models ◽  
Inhomogeneous Cosmological Models ◽  
Higher Dimensional

The search for higher symmetry in string theory

1989 ◽  
Vol 329 (1605) ◽  
pp. 349-357 ◽  
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
String Theory ◽  
Vantage Point ◽  
Higher Symmetry ◽  
Conformal Field ◽  
Soluble Model ◽  
Higher Dimensional ◽  
Dimensional Gravity

Some remarks are made about the nature and role of the search for higher symmetry in string theory. These symmetries are most likely to be uncovered in a mysterious ‘unbroken phase’, for which (2+ 1)-dimensional gravity provides an interesting and soluble model. New insights about conformal field theory, in which one gets ‘out of flatland’ to see a wider symmetry from a higher-dimensional vantage point, may offer clues to the unbroken phase of string theory

Higher-dimensional gauge theories from string theory

2016 ◽  
Vol 64 (4-5) ◽  
pp. 303-316 ◽  
Author(s):  
Alessandro Tomasiello
Keyword(s):  
String Theory ◽  
Gauge Theories ◽  
Higher Dimensional

scholarly journals Conformal frames in cosmology

2016 ◽  
Vol 25 (13) ◽  
pp. 1645006 ◽  
Author(s):  
Guillem Domènech ◽  
Misao Sasaki
Keyword(s):  
String Theory ◽  
Cosmic Microwave Background ◽  
Scalar Fields ◽  
The Other ◽  
Microwave Background ◽  
Classical Level ◽  
Higher Dimensional ◽  
The Universe ◽  
Matter Sector ◽  
Conformal Frames

From higher dimensional theories, e.g. string theory, one expects the presence of nonminimally coupled scalar fields. We review the notion of conformal frames in cosmology and emphasize their physical equivalence, which holds at least at a classical level. Furthermore, if there is a field, or fields, which dominates the universe, as it is often the case in cosmology, we can use such notion of frames to treat our system, matter and gravity, as two different sectors. On one hand, the gravity sector which describes the dynamics of the geometry and on the other hand, the matter sector which has such geometry as a playground. We use this interpretation to build a model where the fact that a curvaton couples to a particular frame metric could leave an imprint in the cosmic microwave background (CMB).

scholarly journals TOPOLOGICAL QUANTUM D-BRANES AND WILD EMBEDDINGS FROM EXOTIC SMOOTH ℝ4

2011 ◽  
Vol 26 (20) ◽  
pp. 3421-3437 ◽  
Author(s):  
TORSTEN ASSELMEYER-MALUGA ◽  
JERZY KRÓL
Keyword(s):  
String Theory ◽  
Classical Limit ◽  
Topological Quantum ◽  
Higher Dimensional

This is the next step of uncovering the relation between string theory and exotic smooth ℝ4. Exotic smoothness of ℝ4 is correlated with D6-brane charges in IIA string theory. We construct wild embeddings of spheres and relate them to a class of topological quantum D p-branes as well to KK theory. These branes emerge when there are nontrivial NS–NS H-fluxes on S3 where the topological classes are determined by wild embeddings S2→S3. Then wild embeddings of higher dimensional p-complexes into Sn correspond to D p-branes. These wild embeddings as constructed by using gropes are basic objects to understand exotic smoothness as well Casson handles. Next we build C⋆-algebras corresponding to the embeddings. Finally we consider topological quantum D-branes as those which emerge from wild embeddings in question. We construct an action for these quantum D-branes and show that the classical limit agrees with the Born–Infeld action such that flat branes = usual embeddings.

scholarly journals Cobordism conjecture, anomalies, and the String Lamppost Principle

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Miguel Montero ◽  
Cumrun Vafa
Keyword(s):  
String Theory ◽  
Gauge Group ◽  
Global Structure ◽  
Dimensional Theory ◽  
Anomaly Cancellation ◽  
Gauge Groups ◽  
Higher Dimensional

Abstract We consider consequences of triviality of cobordism classes and anomaly cancellation in supergravity theories in d > 6. We argue that this leads to the existence of certain defects which we call “I-folds” (a generalization of orientifolds). The requirement that compactifications to lower dimensions involving these defects be anomaly free leads to conditions on the higher dimensional theory. We show that in theories with 16 supercharges in d > 6 this leads to restrictions on the rank of the allowed gauge groups and thus provides an explanation for the observed restrictions in known string theory constructions. In particular, in eight and nine dimensions the only solutions to our constraints are precisely the ones realized in string theory compactifications. We also use these techniques to place constraints on the global structure of the gauge group in eight and nine dimensions.

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