Dual Gauge Theory Research Articles

META-STABLE BRANE CONFIGURATIONS OF TRIPLE PRODUCT GAUGE GROUPS

From an [Formula: see text] supersymmetric electric gauge theory with the gauge group [Formula: see text] with fundamentals for each gauge group and the bifundamentals, we apply Seiberg dual to each gauge group and obtain the [Formula: see text] supersymmetric dual magnetic gauge theories with dual matters including the additional gauge singlets. By analyzing the F-term equations of the dual magnetic superpotentials, we describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of this gauge theory. We apply also to the case for [Formula: see text] supersymmetric electric gauge theory with the gauge group [Formula: see text] with flavors for each gauge group and the bifundamentals. Finally, we describe the meta-stable brane configurations of multiple product gauge groups.

META-STABLE BRANE CONFIGURATIONS OF MULTIPLE PRODUCT GAUGE GROUPS WITH ORIENTIFOLD 6 PLANE

Starting from an [Formula: see text] supersymmetric electric gauge theory with the gauge group [Formula: see text] with fundamentals for each gauge group, the bifundamentals, a symmetric flavor and a conjugate symmetric flavor for SU (Nc), we apply Seiberg dual to each gauge group, obtain the [Formula: see text] supersymmetric dual magnetic gauge theories with dual matters including the gauge singlets, and describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of this gauge theory. We also discuss the case where a symmetric flavor is replaced by an antisymmetric flavor. Next we apply to the case for [Formula: see text] supersymmetric electric gauge theory with the gauge group [Formula: see text] with flavors for each gauge group and the bifundamentals. Finally, we describe the case where the orientifold 6-plane charge is reversed.

A connection between twistors and superstring sigma models on coset superspaces

We consider superstring sigma models that are based on coset superspaces G/H in which H arises as the fixed point set of an order-4 automorphism of G. We show by means of twistor theory that the corresponding first-order system, consisting of the Maurer-Cartan equations and the equations of motion, arises from a dimensional reduction of some generalised self-dual Yang-Mills equations in eight dimensions. Such a relationship might help shed light on the explicit construction of solutions to the superstring equations including their hidden symmetry structures and thus on the properties of their gauge theory duals.

Renormalization, duality, and phase transitions in two- and three-dimensional quantum dimer models

We derive an extended lattice gauge theory type action for quantum dimer models and relate it to the height representations of these systems. We examine the system in two and three dimensions and analyze the phase structure in terms of effective theories and duality arguments. For the two-dimensional case we derive the effective potential both at zero and finite temperature. The zero-temperature theory at the Rokhsar-Kivelson (RK) point has a critical point related to the self-dual point of a class of ${Z}_{N}$ models in the $N\ensuremath{\rightarrow}\ensuremath{\infty}$ limit. Two phase transitions featuring a fixed line are shown to appear in the phase diagram, one at zero temperature and at the RK point and another one at finite temperature above the RK point. The latter will be shown to correspond to a Kosterlitz-Thouless (KT) phase transition, while the former will be governed by a KT-like universality class, i.e., sharing many features with a KT transition but actually corresponding to a different universality class. On the other hand, we show that at the RK point no phase transition happens at finite temperature. For the three-dimensional case we derive the corresponding dual gauge theory model at the RK point. We show in this case that at zero temperature a first-order phase transition occurs, while at finite temperatures both first- and second-order phase transitions are possible, depending on the relative values of the couplings involved.

Finite size corrections for open strings/open chains in planar AdS/CFT

We identify the leading finite-size (Luscher-type) correction to the energy of open strings ending on maximal giant gravitons. In particular we obtain the leading finite size correction at weak 't Hooft coupling and in the planar limit to the energy of very short vacuum states. These results are shown to agree with certain 1, 2, 3 and 4-loop dual gauge theory perturbative calculations, which we also perform.

M2-branes on orbifolds of the cone overQ1,1,1

We study the = 2 supersymmetric Chern-Simons quiver gauge theory recently introduced in arXiv:0809.3237 to describe M2-branes on a cone over the well-known Sasaki-Einstein manifold Q1,1,1. For Chern-Simons levels (k,k,−k,−k) we argue that this theory is dual to AdS4 × Q1,1,1/k. We derive the k orbifold action and show that it preserves geometrical symmetry U(1)R × SU(2) × U(1), in agreement with the symmetry of the gauge theory. We analyze the simplest gauge invariant chiral operators, and show that they match Kaluza-Klein harmonics on AdS4 × Q1,1,1/k. This provides a test of the gauge theory, and in particular of its sextic superpotential which plays an important role in restricting the spectrum of chiral operators. We proceed to study other quiver gauge theories corresponding to more complicated orbifolds of Q1,1,1. In particular, we propose two U(N)4 Chern-Simons gauge theories whose quiver diagrams are the same as in the 4d theories describing D3-branes on a complex cone over F0, a 2 orbifold of the conifold (in 4d the two quivers are related by the Seiberg duality). The manifest symmetry of these gauge theories is U(1)R × SU(2) × SU(2). We argue that these gauge theories at levels (k,k,−k,−k) are dual to AdS4 × Q2,2,2/k. We exhibit calculations of the moduli space and of the chiral operator spectrum which provide support for this conjecture. We also briefly discuss a similar correspondence for AdS4 × M3,2/k. Finally, we discuss resolutions of the cones and their dual gauge theories.

Causality of holographic hydrodynamics

We study causality violation in holographic hydrodynamics in the gauge theory/string theory correspondence, focussing on Gauss-Bonnet gravity. The value of the Gauss-Bonnet coupling is related to the difference between the central charges of the dual conformal gauge theory. We show that, when this difference is sufficiently large, causality is violated both in the second-order truncated theory of hydrodynamics, as well as in the exact theory. We find that the latter provides more stringent constraints, which match precisely those appearing in the CFT analysis of Hofman and Maldacena.

Insightful D-branes

We study a simple model of a black hole in AdS and obtain a holographic description of the region inside the horizon. A key role is played by the dynamics of the scalar fields in the dual gauge theory. This leads to a proposal for a dual description of D-branes falling through the horizon of any AdS black hole. The proposal uses a field-dependent time reparameterization in the field theory. We relate this reparametrization to various gauge invariances of the theory. Finally, we speculate on information loss and the black hole singularity in this context.

Holographic technicolor models and their S-parameter

We study the Peskin-Takeuchi S-parameter of holographic technicolor models. We present the recipe for computing the parameter in a generalized holographic setup. We then apply it to several holographic models that include: (a) the Sakai-Sugimoto model and (b) its non-compactified cousin, (c) a non-critical analog of (a) based on near extremal AdS6 background, (d) the KMMW model which is similar to model (a) but with D6 and anti-D6 flavor branes replacing the D8 and anti-D8 branes, (e) a model based on D5 branes compactified on two S1s with D7 and anti-D7 probe branes and (f) the conifold model with the same probe branes as in (e). The models are gravity duals of gauge theories with SU(NTC) gauge theory and with a breakdown of a flavor symmetry U(NTF) × U(NTF) → UV(NTF). The models (a), (c),(d) and (e) are duals of a confining gauge theories whereas (b) and (f) associate with non confining models. The S-parameter was found to be S=sNTC where s is given by 0.017λTC, 0.016λTC, 0.095, 0.50 and 0.043 for the (a), (b), (c), (d), (f) models respectively and for model (e) s is divergent. These results are valid in the large NTC and large λTC limit. We further derive the dependence of the S-parameter on the ``string endpoint mass of the techniquarks for the various models. We compute the masses of the low lying vector technimesons.

Non chiral dynamical flavors and screening on the conifold

AbstractWe present a new class of string theory solutions which are conjectured to be dual to the 𝒩 = 1 conifold theory by Klebanov and Witten coupled to non chiral massive dynamical flavors. These are introduced, in the Veneziano limit, by means of suitably embedded and smeared D7‐branes whose full backreaction on the background is taken into account. The string solutions are used to study chromoelectric charge screening effects due to the dynamical flavors in the non perturbative regime of the dual gauge theories.

Transversely-intersecting D-branes at finite temperature and chiral phase transition

We consider Sakai-Sugimoto like models consisting of Dq-Dp--branes where Nf flavor Dp and -branes transversely intersect Nc color Dq-branes along two (r+1)-dimensional subspaces. For some values of p and q, the theory of intersections dynamically breaks non-Abelian chiral symmetry which is holographically realized as a smooth connection of the flavor branes at some point in the bulk of the geometry created by Nc Dq-branes. We analyze the system at finite temperature and map out different phases of the theory representing chiral symmetry breaking and restoration. For q ⩽ 4 we find that, unlike the zero-temperature case, there exist two branches of smoothly-connected solutions for the flavor branes, one getting very close to the horizon of the background and the other staying farther away from it. At low temperatures, the solution which stays farther away from the horizon determines the vacuum. For background D5 and D6-branes we find that the flavor branes, like the zero temperature case, show subtle behavior whose dual gauge theory interpretation is not clear. We conclude with some comments on how chiral phase transition in these models can be seen from their open string tachyon dynamics.

The Klebanov-Strassler model with massive dynamical flavors

We present a fully backreacted D3-D7 supergravity solution dual to the Klebanov-Strassler cascading gauge theory coupled to a large number of massive dynamical flavors in the Veneziano limit. The mass of the flavors can be larger or smaller than the dynamically generated scale. The solution is always regular at the origin of the radial coordinate and as such it can be suitably employed to explore the rich IR physics of the dual gauge theory. In this paper we focus on the static quark-antiquark potential, the screening of chromoelectric charges induced by the dynamical flavors, the flux tube breaking and the mass spectrum of the first mesonic excitations. Moreover, we discuss the occurrence of quantum phase transitions in the connected part of the static quark-antiquark potential. Depending on the ratio of certain parameters, like the flavor mass, with respect to some critical values, we find a discontinuous (first order) or smooth transition from a Coulomb-like to a linear phase. We evaluate the related critical exponents finding that they take classical mean-field values and argue that this is a universal feature of analogous first order transitions occurring in the static potential for planar gauge theories having a dual supergravity description.

Quark dynamics, thermal QCD, and the gravity dual

We perform a holographic renormalization of the supergravity action and compute the stress tensor of the dual gauge theory incorporating the logarithmic running of the gauge coupling. From the stress tensor we obtain the shear viscosity and the entropy of the medium at temperature T, and investigate the ratio η / s .

Holographic systematics of D-brane inflation

We provide a systematic treatment of possible corrections to the inflaton potential for D-brane inflation in the warped deformed conifold. We consider the D3-brane potential in the presence of the most general possible corrections to the throat geometry sourced by coupling to the bulk of a compact Calabi-Yau space. This corresponds to the potential on the Coulomb branch of the dual gauge theory, in the presence of arbitrary perturbations of the Lagrangian. The leading contributions arise from perturbations by the most relevant operators that do not destroy the throat geometry. We find a generic contribution from a non-chiral operator of dimension $\Delta=2$ associated with a global symmetry current, resulting in a negative contribution to the inflaton mass-squared. If the Calabi-Yau preserves certain discrete symmetries, this is the dominant correction to the inflaton potential, and fine-tuning of the inflaton mass is possible. In the absence of such discrete symmetries, the dominant contribution comes from a chiral operator with $\Delta=3/2$, corresponding to a $\phi^{3/2}$ term in the inflaton potential. The resulting inflationary models are phenomenologically similar to the inflection point scenarios arising from specific D7-brane embeddings, but occur under far more general circumstances. Our strategy extends immediately to other warped geometries, given sufficient knowledge of the Kaluza-Klein spectrum.

On the Eikonal approximation in AdS space

We explore the eikonal approximation to graviton exchange in AdS_5 space, as relevant to scattering in gauge theories. We restrict ourselves to the regime where conformal invariance of the dual gauge theory holds, and to large 't Hooft coupling where the computation involves pure gravity. We give a heuristic argument, a direct loop computation, and a shock wave derivation. The scalar propagator in AdS_3 plays a key role, indicating that even at strong coupling, two-dimensional conformal invariance controls high-energy four-dimensional gauge-theory scattering.

Towards holographic renormalization of fake supergravity

A step is made towards generalizing the method of holographic renormalization to backgrounds which are not asymptotically AdS, corresponding to a dual gauge theory which has logarithmically running couplings even in the ultraviolet. A prime example is the background of Klebanov–Strassler (KS). In particular, a recipe is given how to calculate renormalized two-point functions for the operators dual to the bulk scalars. The recipe makes use of gauge-invariant variables for the fluctuations around the background and works for any bulk theory of the fake supergravity type. It elegantly incorporates the renormalization scheme dependence of local terms in the correlators. Before applying the method to the KS theory, it is verified that known results in asymptotically AdS backgrounds are reproduced. Finally, some comments on the calculation of renormalized vacuum expectation values are made.

Spiky strings inAdS3×S1and their AdS–pp-wave limits

We study a class of classical solutions for closed strings moving in AdS_3 x S^1 part of AdS_5 x S^5 with energy E and spin S in AdS_3 and angular momentum J and winding m in S^1. They have rigid shape with n spikes in AdS_3. We find that when J or m are non-zero, the spikes do not end in cusps. We consider in detail a special large n limit in which S ~ n^2, J ~ n, i.e. S >> J >> 1, with (E+S)/ n^2, (E-S)/ n, J/n, m/n staying finite. In that limit the spiky spinning string approaches the boundary of AdS_5. We show that the corresponding solution can be interpreted as describing a periodic-spike string moving in AdS_3 --pp-wave x S^1 background. The resulting expression for the string energy should represent a strong-coupling prediction for anomalous dimension of a class of dual gauge theory states in a particular thermodynamic limit of the SL(2) spin chain.

Effect of curvature squared corrections in AdS on the viscosity of the dual gauge theory

We use the real-time finite-temperature AdS/CFT correspondence to compute the effect of general R2 corrections to the gravitational action in AdS space on the shear viscosity of the dual gauge theory. The R2 terms in AdS5 are determined by the central charges of the CFT. We present an example of a four-dimensional gauge theory in which the conjectured lower bound of 1/4π on the viscosity-to-entropy ratio is violated for finite N.

Electric/magnetic duality for chiral gauge theories with anomaly cancellation

We show that 4D gauge theories with Green-Schwarz anomaly cancellation and possible generalized Chern-Simons terms admit a formulation that is manifestly covariant with respect to electric/magnetic duality transformations. This generalizes previous work on the symplectically covariant formulation of anomaly-free gauge theories as they typi- cally occur in extended supergravity, and now also includes general theories with (pseudo- )anomalous gauge interactions as they may occur in global or local N = 1 supersymmetry. This generalization is achieved by relaxing the linear constraint on the embedding tensor so as to allow for a symmetric 3-tensor related to electric and/or magnetic quantum anomalies in these theories. Apart from electric and magnetic gauge fields, the resulting Lagrangians also feature two-form fields and can accommodate various unusual duality frames as they often appear, e.g., in string compactifications with background fluxes.

R2curvature-squared corrections on drag force

The effect of finite-coupling corrections to the drag force on a moving heavy quark in the Super Yang-Mills plasma is investigated. These corrections are related to curvature-squared corrections in the corresponding gravity dual. The results are compared with the dual gauge theory. It is shown that curvature-squared corrections affect the drag force. It is shown that corrections to the drag force depend on the velocity of the heavy quark. The diffusion coefficient of non-relativistic heavy quarks is calculated from the drag force. In addition, we also calculate the drag force on a moving heavy quark in the Gauss-Bonnet background.