We calculate an unrefined limit of the superconformal index (the Schur-like index) of the Klebanov-Witten theory from the dual AdS side by using the recently developed giant graviton expansion method. Our formula includes multiple sums of the contribution of the D3-branes wrapped on three-cycles in the internal space. We numerically confirm the validity of our formula by comparing indices obtained by the formula with the gauge theory results.
In this paper we consider both Abelian as well as non-Abelian T-duals of the Klebanov-Witten background and inspect their various Penrose limits. We show that these backgrounds admit pp-wave solutions in the neighbourhood of appropriate null geodesics. We study the quantization of closed string propagating on some of the resulting pp-wave backgrounds and comment on the probable field theory duals.
We probe flavour branes in the Klebanov-Witten background in global coordinates. We show that supersymmetric probes correspond to massless flavours and analyse their spectrum of fluctuations. Our studies suggest that the mesons are dissociated by the Casimir energy. The spectrum is equidistant, with a ground state given by the conformal dimension of the operator dual to the fluctuations. We show that the equidistant structure of the spectrum arises from the addition of the angular momenta of the fundamental fields composing the meson operators.
We investigate 1/2 BPS conformal surface operators in the Klebanov-Witten theory. These surface operators preserve certain parts of the conformal symmetry and R-symmetry as well as half of the supersymmetry. We propose the gravity dual of the surface operator as a configuration of a D3-brane in AdS_5 x T^{1,1}. This D3-brane preserves the same amount of the supersymmetry as the surface operator. We also compute the correlation function of the surface operator and a chiral primary operator.
We study renormalization group flows among three dimensional superconformal gauge theories which closely resemble the renowned Klebanov-Witten flow in four dimensions. In the large N limit, each theory appearing in the flow is holographically dual to M-theory on AdS4 times a toric Sasaki-Einstein seven-manifold. The theories are obtained through the so-called flavoring method, which adds some fundamental matter fields to the dimensionally reduced Klebanov-Witten theories. We reconfirm the matching between the gauge theories and the dual geometries by comparing the chiral ring structure. As a m…
Using AdS/CFT, we study the addition of an arbitrary number of backreacting flavors to the Klebanov-Witten theory, making many checks of consistency between our new Type IIB plus branes solution and expectations from field theory. We study generalizations of our method for adding flavors to all N=1 SCFTs that can be realized on D3-branes at the tip of a Calabi-Yau cone. Also, general guidelines suitable for the addition of massive flavor branes are developed.
We study oscillating string solutions in the Klebanov-Witten and its non-Abelian T-dual background dualised along an SU(2) isometry. We find the string energy as the function of oscillation number and angular momentum. We show that for a particular set of T-dual co-ordinates both the background have equal string states. We also study the string states where the strings are expanding and contracting in the T-dual co-ordinate direction. We expect the presence of the superconformal field theory dual operators whose anomalous dimensions depend on T-dual co-ordinate.
In this paper we find various new backgrounds in Type IIB, IIA and M-theory with an $AdS_3$-factor. The solutions are smooth and preserve small amounts of SUSY. These new backgrounds are found by application of non-Abelian T-duality (sometimes combined with T-duality) on the supergravity solution dual to the Klebanov-Witten CFT compactified to two dimensions. The field theory aspects encoded by these backgrounds are studied. We give a detailed account of conserved charges, central charges, entanglement entropy and Wilson loops. Further, we present a possible field theory interpretation for our…
In this paper we study an $AdS_5$ solution constructed using non-Abelian T-duality, acting on the Klebanov-Witten background. We show that this is dual to a linear quiver with two tails of gauge groups of increasing rank. The field theory dynamics arises from a D4-NS5-NS5' brane set-up, generalizing the constructions discussed by Bah and Bobev. These realize $\mathcal{N}=1$ quiver gauge theories built out of $\mathcal{N}=1$ and $\mathcal{N}=2$ vector multiplets flowing to interacting fixed points in the infrared. We compute the central charge using $a$-maximization, and show its precise agreem…
We study D-instanton solutions in type IIB supergravity on $AdS_5\times T^{1,1}$, which has a dual ${\cal N}=1$ $SU(N)\times SU(N)$ super Yang-Mills theory. Apart from ordinary D(-1)-brane instantons, we discuss wrapped D1-branes over minimal 2-cycles and derive explicit solutions preserving half the supersymmetries. These solutions are identified with Yang-Mills instantons which are (anti)self-dual in both gauge group factors with instanton charge $(k,k')$. By examining the boundary behaviour of the solutions we discuss the coupling to the corresponding dual boundary operators, and identify t…
We consider the addition of a large number of massive dynamical flavors to the Klebanov-Witten theory, the quiver gauge theory describing the low energy dynamics of Nc D3-branes at the conifold singularity. Massive flavors are introduced by means of Nf D7-branes which are holomorphically embedded and smeared along the transverse directions. After some general comments on the validity of the smearing procedure, we find the full backreacted supergravity solution corresponding to a particular class of massive embeddings. The solution depends on a running effective number of flavors, whose functio…
In this sequel to [L-Y1], [L-L-S-Y], and [L-Y2] (respectively arXiv:0709.1515 [math.AG], arXiv:0809.2121 [math.AG], and arXiv:0901.0342 [math.AG]), we study a D-brane probe on a conifold from the viewpoint of the Azumaya structure on D-branes and toric geometry. The details of how deformations and resolutions of the standard toric conifold $Y$ can be obtained via morphisms from Azumaya points are given. This should be compared with the quantum-field-theoretic/D-brany picture of deformations and resolutions of a conifold via a D-brane probe sitting at the conifold singularity in the work of Kle…
We consider three-parameter Yang-Baxter deformations of the $AdS_5\times T^{1,1}$ superstring for abelian $r$-matrices which are solutions of the classical Yang-Baxter equation. We find two new backgrounds which are dual to the dipole deformed Klebanov-Witten gauge theory and to the nonrelativistic Klebanov-Witten gauge theory with Schrödinger symmetry
We study semiclassical strings in the Klebanov-Witten and in the Non-abelian T-dual Klebanov-Witten backgrounds. We show that both backgrounds share a subsector of equivalent states up to conditions on the T-dual coordinates which also impose a breaking of the R-symmetry by a discrete group. We also analyze string configurations where the strings are stretched along the T-dual coordinates. This semiclassical analysis predicts the existence of chiral primary operators for the dual (strongly coupled) superconformal field theory whose anomalous dimension depends on the T-dual coordinates. We brie…
We examine the extension of the Klebanov-Witten gauge/gravity correspondence away from the low-energy conformal limit, to a duality involving the full, asymptotically Ricci-flat background describing three-branes on the conifold. After a discussion of the nature of this duality at the string theory level (prior to taking any limits), we concentrate on the intermediate-energy regime where excited string modes are negligible but the branes are still coupled to the bulk. Building upon previous work, we are able to characterize the effective D3-brane worldvolume action in this regime as an IR defo…
We expand on Klebanov and Witten's recent proposal for formulating the AdS/CFT correspondence using irregular boundary conditions. The proposal is shown to be correct to any order in perturbation theory.
We show that the entanglement of purification and the critical distance between the two mixed systems is a powerful measure in probing the phase structures of QCD and confining backgrounds, as it can distinguish the scale of chiral symmetry breaking versus the scale of confinement/deconfinement phase transitions. For two symmetric strips with equal and finite width and infinite length, and in the background of several confining geometries, we numerically calculate the critical distance between them where the mutual information vanishes and show that this quantity can probe the very rich phase …
The Witten index counts the difference in the number of bosonic and fermionic states of a quantum mechanical system. The Schur index, which can be defined for theories with at least $\mathcal{N}=2$ supersymmetry in four dimensions is a particular refinement of the index, dependent on one parameter $q$ serving as the fugacity for a particular set of charges which commute with the hamiltonian and some supersymmetry generators. This index has a known expression for all Lagrangian and some non-Lagrangian theories as a finite dimensional integral or a complicated infinite sum. In the case of $\math…
In hep-th/9803002, Maldacena argued that in the light of the AdS/CFT correspondence as formulated by Witten and Gubser, Klebanov and Polyakov as a relation between partition functions, the expectation value of the Wilson loop in $\cal N$=4 SU(N) SYM is given by the worldsheet partition function with the action formulated on an $AdS_5\times S^5$ background and the world sheet ending on the loop on the boundary of $AdS_5$. What we propose to do in this paper is to provide some alternative arguments as to why it should be so.
We consider the behavior of D7 probes of supersymmetric warped geometries that are perturbed by the presence of anti-D3-branes. Such constructions are the gravitational duals of non-supersymmetric states in supersymmetric flavored gauge theories. Although the D7s that we consider do not feel a force from either D3s or anti-D3s alone, when both types of 3-branes are present the D7s deform and fall a small distance toward the 3-branes. We perform our analysis in AdS^5 x S^5 and the Klebanov-Witten solution and find qualitatively similar behavior in each case. We then extend our consideration to …
In a recent paper Klebanov and Witten (hep-th/9905104) proposed to formulate the AdS/CFT correspondence principle by taking an "irregular boundary condition" for a scalar field. In this paper we generalize this idea to the case of spinor field with interaction. The action functional following from the choice of irregular boundary conditions and which must be used in the AdS/CFT correspondence is related to the usual action by a Legendre transform. For the new theory we found the modified Green's function that must be used for internal lines in calculating higher order graphs. It is proved that…
We conjecture a formula for the Schur index of N=2 four-dimensional theories in the presence of boundary conditions and/or line defects, in terms of the low-energy effective Seiberg-Witten description of the system together with massive BPS excitations. We test our proposal in a variety of examples for SU(2) gauge theories, either conformal or asymptotically free. We use the conjecture to compute these defect-enriched Schur indices for theories which lack a Lagrangian description, such as Argyres-Douglas theories. We demonstrate in various examples that line defect indices can be expressed as …
In this thesis we study some applications of the gauge/gravity correspondence. In chapter 1 we introduce the gauge/gravity conjecture focusing on the aspects that will be relevant in the rest of the work, in chapter 2 we extend the Gubser-Klebanov-Polyakov-Witten (GKPW) prescription generalizing it to gravity backgrounds with two boundaries. In chapter 3 we discuss the Maldacena-Rey prescription to compute the quark-antiquark (and monopole-antimonopole) potential in some gravity backgrounds duals to conformal and non-conformal field theories. In particular, we analyze the stability of the clas…
It was proposed by Maldacena that the large $N$ limit of certain conformal field theories can be described in terms of supergravity on anti-De Sitter spaces (AdS). Recently, Gubser, Klebanov and Polyakov and Witten have conjectured that the generating functional for certain correlation functions in conformal field theory is given by the classical supergravity action on AdS. It was shown that the spectra of states of the two theories are matched and the two-point correlation function was studied. We discuss the interacting case and compare the three- and four-point correlation functions compute…
A method to solve various aspects of the strong coupling expansion of the superconformal field theory duals of AdS_5 x X geometries from first principles is proposed. The main idea is that at strong coupling the configurations that dominate the low energy dynamics of the field theory compactified on a three sphere are given by certain non-trivial semi-classical configurations in the moduli space of vacua. We show that this approach is self-consistent and permits one to express most of the dynamics in terms of an effective N=4 SYM dynamics. This has the advantage that some degrees of freedom th…
We speculate that the weak gravity conjecture applied to theories with holographic duals bans the existence of disordered phases at zero temperature. We test this idea by introducing a non-zero baryon chemical potential in a deformation of the $SU(N_c)\times SU(N_c)$ Klebanov-Witten gauge theory with broken supersymmetry and conformal invariance. At low temperature, a disordered phase dual to a black brane geometry is unstable for low chemical potentials and metastable for high values. In the metastable phase, states with a partial Higgsing of the gauge group are favored over the normal disord…
