Backreacted flavor in non-commutative gauge theories

We construct the gravity dual of N = 1 Non-Commutative SYM theory coupled to N_f smeared massless fundamental flavors. Our solution is analytic and non-perturbative. Near the origin the background reduces to the one corresponding to an ordinary SYM theory. At large radial distances, the dilaton diverges signaling the presence of a UV Landau pole. Considering a probe D3–brane we calculate the effective YM coupling and show that it is independent on the parameter of non-commutativity. We calculate the corresponding beta function and show that it remains positive at all energy scales

Mesons from (non) Abelian T-dual backgrounds

In this work we study mesonic excitations in a Quantum Field Theory dual to the non Abelian T-dual of $AdS_5\times S^5$, using a D6 brane probe on the Sfetsos-Thompson background. Before and after the duality, we observe interesting differences between the spectra and interpret them. The spectrum of masses and the interactions among mesonic excitations teach valuable lessons about the character of non-Abelian T-duality and its implications for Holography. The case of Abelian T-duality is also studied.Comment: 26 pages plus many long appendice

Spacetimes for λ-deformations

We examine a recently proposed class of integrable deformations to two-dimensional conformal field theories. These {\lambda}-deformations interpolate between a WZW model and the non-Abelian T-dual of a Principal Chiral Model on a group G or, between a G/H gauged WZW model and the non-Abelian T-dual of the geometric coset G/H. {\lambda}-deformations have been conjectured to represent quantum group q-deformations for the case where the deformation parameter is a root of unity. In this work we show how such deformations can be given an embedding as full string backgrounds whose target spaces satisfy the equations of type-II supergravity. One illustrative example is a deformation of the Sl(2,R)/U(1) black-hole CFT. A further example interpolates between the SU(2)×SU(2)SU(2)×SL(2,R)×SL(2,R)SL(2,R)×U(1)4 gauged WZW model and the non-Abelian T-dual of AdS3×S3×T4 supported with Ramond flux

Type IIB supergravity solutions with AdS5 from Abelian and non-Abelian T dualities

We present a large class of new backgrounds that are solutions of type IIB supergravity with a warped AdS${}_5$ factor, non-trivial axion-dilaton, $B$-field and three-form Ramond-Ramond flux but yet have no five-form flux. We obtain these solutions and many of their variations by judiciously applying non-Abelian and Abelian T-dualities, as well as coordinate shifts to AdS${}_5\times X_5$ IIB supergravity solutions with $X_5=S^5, T^{1,1}, Y^{p,q}$. We address a number of issues pertaining to charge quantization in the context of non-Abelian T-duality. We comment on some properties of the expected dual super conformal field theories by studying their CFT central charge holographically. We also use the structure of the supergravity Page charges, central charges and some probe branes to infer aspects of the dual super conformal field theories.Comment: 71 pages, one table. v2: References added, some normalizations corrected, results unchange

Beta function of k deformed AdS5 × S 5 string theory

We calculate the one loop beta function for the would-be marginal coupling on the world sheet of the k deformed sigma models associated to a quantum group with q=exp(i pi/k). This includes the bosonic principal chiral models and symmetric space sigma models but also the k deformed semi-symmetric space sigma model describing strings in a deformation of AdS_5 x S^5. The world sheet sigma model is a current-current deformation of the gauged WZW model for the supergroup PSU(2,2|4) with level k. In the string theory context the beta function is shown to vanish because of the vanishing of the Killing form of PSU(2,2|4) which is another piece of evidence that the k deformed theories define consistent string theories.Comment: 26 pages, some typos correcte

New N N \mathcal{N} =1 supersymmetric AdS 5 backgrounds in type IIA supergravity

We present a family of N=1 supersymmetric backgrounds in type-IIA supergravity and their lifts to eleven-dimensional supergravity. These are of the form AdS5×X5 and are characterised by an SU(2) structure. The internal space, X5, is obtained from the known Sasaki-Einstein manifolds, Yp,q, via an application of non-Abelian T-duality

Field theory aspects of non-Abelian T-duality and N = 2 linear quivers

In this paper we propose a linear quiver with gauge groups of increasing rank as field theory dual to the AdS 5 background constructed by Sfetsos and Thompson through non-Abelian T-duality. The formalism to study 4d N = 2 SUSY CFTs developed by Gaiotto and Maldacena is essential for our proposal. We point out an interesting relation between (Hopf) Abelian and non-Abelian T-dual backgrounds that allows to see both backgrounds as different limits of a solution constructed by Maldacena and Núñez. This suggests different completions of the long quiver describing the CFT dual to the nonAbelian T-dual background that match different observables

The non-integrability of strings in massive type IIA and their holographic duals

In this work we study various aspects of six-dimensional ${\cal N}=(1,0)$ SCFTs. We consider the construction of their string duals in Massive IIA and discuss some observables in given examples. We study the dynamics of string solitons wrapping and rotating on the Massive IIA background and show that the associated Hamiltonian system is both non-integrable and chaotic, implying the non-integrability of the dual CFT. Our procedure is analytic, using well developed mathematical techniques, and numerical, by the explicit calculation of power spectra, Lyapunov coefficients and Poincar\'e sections.Comment: 28 pages plus appendices. Various figures. Some clarifications and references adde

Holographic flows in non-Abelian T-dual geometries

We use non-Abelian T-duality to construct new N=1 solutions of type IIA supergravity (and their M-theory lifts) that interpolate between AdS_5 geometries. We initiate a study of the holographic interpretation of these backgrounds as RG flows between conformal fixed points. Along the way we give an elegant formulation of non-Abelian T-duality when acting on a wide class of backgrounds, including those corresponding to such flows, in terms of their SU(2) structure