scholarly journals Warped anti-de Sitter spaces from brane intersections in type II string theory

2010 ◽  
Vol 2010 (6) ◽  
Author(s):  
Domenico Orlando ◽  
Linda I. Uruchurtu
Keyword(s):  
String Theory ◽  
Type Ii ◽  
De Sitter

scholarly journals Refining the boundaries of the classical de Sitter landscape

2017 ◽  
Vol 2017 (3) ◽  
Author(s):  
David Andriot ◽  
Johan Blåbäck
Keyword(s):  
String Theory ◽  
Compact Manifold ◽  
Cosmological Models ◽  
Ricci Scalar ◽  
General Interest ◽  
De Sitter Spacetime ◽  
Type Ii ◽  
De Sitter ◽  
Technical Aspects ◽  
Sitter Spacetime

Abstract We derive highly constraining no-go theorems for classical de Sitter backgrounds of string theory, with parallel sources; this should impact the embedding of cosmological models. We study ten-dimensional vacua of type II supergravities with parallel and backreacted orientifold O p -planes and D p -branes, on four-dimensional de Sitter spacetime times a compact manifold. Vacua for p = 3, 7 or 8 are completely excluded, and we obtain tight constraints for p = 4, 5, 6. This is achieved through the derivation of an enlightening expression for the four-dimensional Ricci scalar. Further interesting expressions and no-go theorems are obtained. The paper is self-contained so technical aspects, including conventions, might be of more general interest.

scholarly journals SO(3)×U(1) Isometric Instantons with Non-Abelian Hair in Four-Dimensional String Theory

1997 ◽  
Vol 12 (25) ◽  
pp. 1847-1858
Author(s):  
Adrián R. Lugo
Keyword(s):  
String Theory ◽  
Type Ii ◽  
Dimensional Solution ◽  
Coset Model

We compute the exact effective string vacuum backgrounds of the level k=81/19 SU(2,1)/U(1) coset model. A compact SU(2) isometry present in this seven-dimensional solution allows one to interpret it after compactification as a four-dimensional non-Abelian SU(2) charged instanton with a singular submanifold and an SO(3) × U(1) isometry. The semiclassical backgrounds, solutions of the type II strings, present similar characteristics

scholarly journals Unimodular vs nilpotent superfield approach to pure dS supergravity

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sukruti Bansal ◽  
Silvia Nagy ◽  
Antonio Padilla ◽  
Ivonne Zavala
Keyword(s):  
String Theory ◽  
General Framework ◽  
Recent Progress ◽  
High Energy ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
New Approach ◽  
Sitter Spacetime ◽  
Novel Approach ◽  
De Sitter Vacua

Abstract Recent progress in understanding de Sitter spacetime in supergravity and string theory has led to the development of a four dimensional supergravity with spontaneously broken supersymmetry allowing for de Sitter vacua, also called de Sitter supergravity. One approach makes use of constrained (nilpotent) superfields, while an alternative one couples supergravity to a locally supersymmetric generalization of the Volkov-Akulov goldstino action. These two approaches have been shown to give rise to the same 4D action. A novel approach to de Sitter vacua in supergravity involves the generalisation of unimodular gravity to supergravity using a super-Stückelberg mechanism. In this paper, we make a connection between this new approach and the previous two which are in the context of nilpotent superfields and the goldstino brane. We show that upon appropriate field redefinitions, the 4D actions match up to the cubic order in the fields. This points at the possible existence of a more general framework to obtain de Sitter spacetimes from high-energy theories.

scholarly journals Logarithmic loop corrections, moduli stabilisation and de Sitter vacua in string theory

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Ignatios Antoniadis ◽  
Yifan Chen ◽  
George K. Leontaris
Keyword(s):  
String Theory ◽  
De Sitter ◽  
De Sitter Vacua

scholarly journals DUALITY AND SELF-DUAL TRIPLET SOLUTIONS IN EUCLIDEAN GRAVITY

1996 ◽  
Vol 11 (34) ◽  
pp. 2669-2679
Author(s):  
SWAPNA MAHAPATRA
Keyword(s):  
String Theory ◽  
The Self ◽  
Target Space ◽  
De Sitter ◽  
Gravitational Instanton ◽  
Duality Symmetry ◽  
Sitter Solution

Starting from the self-dual “triplet” of gravitational instanton solutions in Euclidean gravity, we obtain the corresponding instanton solutions in string theory by making use of the target space duality symmetry. We show that these dual triplet solutions can be obtained from the general dual Taub-NUT de Sitter solution through some limiting procedure as in the Euclidean gravity case. The dual gravitational instanton solutions obtained here are self-dual for some cases, with respect to certain isometries, but not always.

HOLOGRAPHIC SPACETIME

2012 ◽  
Vol 21 (11) ◽  
pp. 1241004 ◽  
Author(s):  
TOM BANKS
Keyword(s):  
String Theory ◽  
Degrees Of Freedom ◽  
Good Description ◽  
De Sitter ◽  
Finite Radius ◽  
Full Field ◽  
Mass Scaling ◽  
Finite Dimensional ◽  
Emergent Phenomena ◽  
Holographic Screen

The theory of holographic spacetime (HST) generalizes both string theory and quantum field theory (QFT). It provides a geometric rationale for supersymmetry (SUSY) and a formalism in which super-Poincare invariance follows from Poincare invariance. HST unifies particles and black holes, realizing both as excitations of noncommutative geometrical variables on a holographic screen. Compact extra dimensions are interpreted as finite-dimensional unitary representations of super-algebras, and have no moduli. Full field theoretic Fock spaces, and continuous moduli are both emergent phenomena of super-Poincare invariant limits in which the number of holographic degrees of freedom goes to infinity. Finite radius de Sitter (dS) spaces have no moduli, and break SUSY with a gravitino mass scaling like Λ1/4. In regimes where the Covariant Entropy Bound is saturated, QFT is not a good description in HST, and inflation is such a regime. Following ideas of Jacobson, the gravitational and inflaton fields are emergent classical variables, describing the geometry of an underlying HST model, rather than "fields associated with a microscopic string theory". The phrase in quotes is meaningless in the HST formalism, except in asymptotically flat and AdS spacetimes, and some relatives of these.

scholarly journals EXTREME DYONIC BLACK HOLES IN STRING THEORY

1996 ◽  
Vol 11 (09) ◽  
pp. 689-713 ◽  
Author(s):  
A.A. TSEYTLIN
Keyword(s):  
Black Holes ◽  
String Theory ◽  
Short Distance ◽  
Black Hole Entropy ◽  
Universal Relation ◽  
Type Ii ◽  
Statistical Entropy ◽  
Five Dimensions ◽  
Compact Dimension ◽  
Lower Dimensional

Supersymmetric extreme dyonic black holes of toroidally compactified heterotic or type-II string theory can be viewed as lower-dimensional images of solitonic strings wound around a compact dimension. We consider conformal sigma models which describe string configurations corresponding to various extreme dyonic black holes in four and five dimensions. These conformal models have regular short-distance region equivalent to a WZW theory with level proportional to magnetic charges. Arguments are presented suggesting a universal relation between the black hole entropy (area) and the statistical entropy of BPS-saturated oscillation states of solitonic string.

scholarly journals Advances in String Theory in Curved Backgrounds: A Synthesis Report

2003 ◽  
Vol 18 (12) ◽  
pp. 2011-2022 ◽  
Author(s):  
N. G. Sanchez
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
String Theory ◽  
Quantum Field ◽  
De Sitter ◽  
Conformal Field ◽  
Dual Relation ◽  
New Feature ◽  
Synthesis Report ◽  
Gravitational Wave Background

A synthetic report of the advances in the study of classical and quantum string dynamics in curved backgrounds is provided, namely : the new feature of Multistring solutions; the mass spectrum of Strings in Curved backgrounds; The effect of a Cosmological Constant and of Spacial Curvature on Classical and Quantum Strings; Classical splitting of Fundamental Strings; The General String Evolution in constant Curvature Spacetimes; The Conformal Invariance Effects; Strings on plane fronted and gravitational shock waves, string falling on spacetime singularities and its spectrum. New Developments in String Gravity and String Cosmology are reported: String driven cosmology and its Predictions; The primordial gravitational wave background; Non-singular string cosmologies from Exact Conformal Field Theories; Quantum Field Theory, String Temperature and the String Phase of de Sitter space-time; Hawking Radiation in String Theory and the String Phase of Black Holes; New Dual Relation between Quantum Field Theory regime and String regime and the "QFT/String Tango"; New Coherent String States and Minimal Uncertainty Principle in string theory.

scholarly journals Towards classical de Sitter solutions in string theory

2009 ◽  
Vol 2009 (09) ◽  
pp. 114-114 ◽  
Author(s):  
Ulf H Danielsson ◽  
Sheikh Shajidul Haque ◽  
Gary Shiu ◽  
Thomas Van Riet
Keyword(s):  
String Theory ◽  
De Sitter
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