DUALITY IN STRING THEORY

2013 ◽  
Vol 10 (08) ◽  
pp. 1360003
Author(s):  
YOLANDA LOZANO

Duality symmetries have played a key role in the discovery that the five consistent superstring theories in 10 dimensions emerge as different corners of the moduli space of a single unifying theory, known as M-theory. Focusing on the target space, or T, duality symmetry, we show how it can be formulated in spacetimes with abelian and non-abelian isometries. Finally, we discuss some recent work that realizes non-abelian T-duality as a consistent truncation to seven-dimensional supergravity, thus generalizing to the non-abelian case the realization of abelian T-duality at the supergravity level.

1996 ◽  
Vol 11 (34) ◽  
pp. 2669-2679
Author(s):  
SWAPNA MAHAPATRA

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.


2020 ◽  
Vol 2020 (7) ◽  
Author(s):  
Yuho Sakatani ◽  
Shozo Uehara

Abstract The $T$-duality of string theory can be extended to the Poisson–Lie $T$-duality when the target space has a generalized isometry group given by a Drinfel’d double. In M-theory, $T$-duality is understood as a subgroup of $U$-duality, but the non-Abelian extension of $U$-duality is still a mystery. In this paper we study membrane theory on a curved background with a generalized isometry group given by the $\mathcal E_n$ algebra. This provides a natural setup to study non-Abelian $U$-duality because the $\mathcal E_n$ algebra has been proposed as a $U$-duality extension of the Drinfel’d double. We show that the standard treatment of Abelian $U$-duality can be extended to the non-Abelian setup. However, a famous issue in Abelian $U$-duality still exists in the non-Abelian extension.


2004 ◽  
Vol 19 (04) ◽  
pp. 521-555 ◽  
Author(s):  
GOTTFRIED CURIO

The membrane instanton superpotential for M-theory on the G2 holonomy manifold given by the cone on S3×S3 is given by the dilogarithm and has Heisenberg monodromy group in the quantum moduli space. We compare this to a Heisenberg group action on the type IIA hypermultiplet moduli space for the universal hypermultiplet, to metric corrections from membrane instantons related to a twisted dilogarithm for the deformed conifold and to a flat bundle related to a conifold period, the Heisenberg group and the dilogarithm appearing in five-dimensional Seiberg/Witten theory.


2000 ◽  
Vol 15 (12) ◽  
pp. 1707-1756 ◽  
Author(s):  
G. V. KRANIOTIS

In this work, we review recent work on string cosmology. The need for an inflationary era is well known. Problems of Standard Cosmology such as horizon, flatness, monopole and entropy find an elegant solution in the inflationary scenario. On the other hand no adequate inflationary model has been constructed so far. In this review we discuss the attempts that have been made in the field of string theory for obtaining an adequate Cosmological Inflationary Epoch. In particular, orbifold compactifications of string theory which are constrained by target-space duality symmetry offer as natural candidates for the role of inflatons the orbifold moduli. Orbifold moduli dynamics is very constrained by duality symmetry and offers a concrete framework for discussing Cosmological Inflation. We discuss the resulting cosmology assuming that nonperturbative dynamics generates a moduli potential which respects target-space modular invariance. Various modular forms for the nonperturbative superpotential and Kähler potential which include the absolute modular invariant j(T) besides the Dedekind eta function η(T) are discussed. We also review scale-factor duality and pre-Big-Bang scenarios in which inflation is driven by the kinetic terms of the dilaton modulus. In this context we discuss the problem of graceful exit and review recent attempts for solving the problem of exiting from inflation. The possibility of obtaining inflation through the D-terms in string models with anomalous UA(1) and other Abelian factors is reviewed. In this context we discuss how the slow-roll problem in supergravity models with F-term inflation can be solved by D-term inflation. We also briefly review the consequences of duality for a generalized Heisenberg uncertainty principle and the structure of space–time at short scales. The problem of the Cosmological Constant is also briefly discussed.


1994 ◽  
Vol 09 (21) ◽  
pp. 3707-3750 ◽  
Author(s):  
ASHOKE SEN

We present several pieces of evidence for strong–weak coupling duality symmetry in the heterotic string theory, compactified on a six-dimensional torus. They include symmetry of the (1) low energy effective action, (2) allowed spectrum of electric and magnetic charges in the theory, (3) allowed mass spectrum of particles saturating the Bogomol'nyi bound, and (4) Yukawa couplings between massless neutral particles and massive charged particles saturating the Bogomol'nyi bound. This duality transformation exchanges the electrically charged elementary string excitations with the magnetically charged soliton states in the theory. It is shown that the existence of a strong–weak coupling duality symmetry in four-dimensional string theory makes definite predictions about the existence of new stable monopole and dyon states in the theory with specific degeneracies, including certain supersymmetric bound states of monopoles and dyons. The relationship between strong–weak coupling duality transformation in string theory and target space duality transformation in the five-brane theory is also discussed.


2016 ◽  
Vol 31 (01) ◽  
pp. 1650001
Author(s):  
Samrat Bhowmick

U-duality symmetry of M-theory and S- and T-duality of string theory can be used to study various black brane solutions. We explore some aspect of this idea here. This symmetry can be used to get relations among various components of the metric of the black brane. These relations in turn give relations among various components of the energy–momentum tensor. We show that, using these relations, without knowing the explicit form of form fields, we can get the black brane solutions. These features were studied previously in the context of M-theory. Here, we extensively studied them in string theory (type II supergravity). We also show that this formulation works for exotic branes. We give an example of a time-dependent system where this method is essential.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Sergei Alexandrov ◽  
Ashoke Sen ◽  
Bogdan Stefański

Abstract Type IIA string theory compactified on a Calabi-Yau threefold has a hypermultiplet moduli space whose metric is known to receive non-perturbative corrections from Euclidean D2-branes wrapped on 3-cycles. These corrections have been computed earlier by making use of mirror symmetry, S-duality and twistorial description of quaternionic geometries. In this paper we compute the leading corrections in each homology class using a direct world-sheet approach without relying on any duality symmetry or supersymmetry. Our results are in perfect agreement with the earlier predictions.


2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
José J Fernández-Melgarejo ◽  
Yuho Sakatani ◽  
Shozo Uehara

Abstract Type II string theory or M-theory contains a broad spectrum of gauge potentials. In addition to the standard $p$-form potentials, various mixed-symmetry potentials have been predicted, which may couple to exotic branes with non-standard tensions. Together with $p$-forms, mixed-symmetry potentials turn out to be essential to build the multiplets of the $U$-duality symmetry in each dimension. In this paper, we systematically determine the set of mixed-symmetry potentials and exotic branes on the basis of the $E_{11}$ conjecture. We also study the decompositions of $U$-duality multiplets into $T$-duality multiplets and determine which mixed-symmetry tensors are contained in each of the $U$-/$T$-duality multiplets.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
H. Mahmood ◽  
R. A. Reid-Edwards

Abstract We reconsider some older constructions of T-duality, based on automorphisms of the worldsheet operator algebra, in a modern context. It has been long known that at special points in the moduli space of torus compactifications, the target space gauge symmetry may be enhanced. Away from such points the symmetry is broken and T-duality may be understood as a residual discrete gauge symmetry that survives this breaking. Drawing on work on connections over the space of string backgrounds, we discuss how to generalise this framework for T-duality to geometric and non-geometric backgrounds that are not full solutions of string theory, but may play an important role in exact backgrounds. Along the way we find an interesting algebraic structure and discuss its relationship with doubled geometry. We comment on non-isometric T-duality in this context.


2020 ◽  
Vol 29 (06) ◽  
pp. 2030005
Author(s):  
Gaston Giribet

We review old and recent results on a special limit of string theory on [Formula: see text] with pure NS–NS fluxes: the limit in which the string length [Formula: see text] equals the [Formula: see text] radius [Formula: see text]. At this point of the moduli space, the theory exhibits special properties, which we discuss. Special attention is focused on features of correlation functions that are related to the noncompactness of the boundary CFT target space, and on how these features change when the point [Formula: see text] is approached. Also, we briefly review the recent proposals for exact realizations of AdS/CFT correspondence at this special point.


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