arXiv subjects

Ricardo Stuardo

Publications and source records attributed to Ricardo Stuardo.

18 recordsLinked to original sources

arXiv2026

Monodromy Defects in Maximally Supersymmetric Yang-Mills Theories from Holography

We study three Type II supergravity solutions holographically dual to codimension-2 supersymmetric defects in $(p+1)$-dimensional SU($N$) maximally supersymmetric Yang-Mills theory ($p=2,3,4$). In all of these cases, the defects have a non-trivial monodromy for the maximal abelian subgroup for the SO($9-p$) R-symmetry. Such solutions are obtained by considering branes wrapping spindle configurations, changing the parameters (which alters the coordinate domain), and imposing suitable boundary conditions. We provide a prescription to compute the entanglement entropy of the effective theory on the defect. We find the resulting quantity to be proportional to the free energy of the ambient theory. A similar analysis is performed for the D5-brane wrapping a spindle, but we find that changing the coordinate domain does not lead to a defect solution, but rather to a circle compactification.

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arXiv2026

(Iso)spin from Isospin in Top-Down Holography

Motivated by the spin from isospin mechanism of Jackiw-Rebbi-Hasenfratz-'t Hooft, we study two SU(2) gauged supergravity solutions of the form $M_{d}\times\text{S}^{2}$ containing non-Abelian hedgehog monopole on the 2-sphere. Due to the presence of the monopole, the SO(3) isometry group of the 2-sphere is not a symmetry of the configuration. Instead, a diagonal combination of the SU(2) gauge and the SO(3) isometry of the 2-sphere is the true symmetry of the configuration. Uplifting the solutions to Type II, the gauge-isometry diagonal symmetry becomes a diagonal combination between the SO(3) symmetry of the 2-sphere and a SU(2) symmetry of a 3-sphere used to uplift the configuration. One of the uplifts is supersymmetric and corresponds to the I-brane theory on a 2-sphere. The second background is a deformation of $\text{AdS}_{5}\times\text{S}^{5}$ and is not supersymmetric. We study dilaton fluctuations on the later geometry. Due to the diagonal symmetry, the fluctuations show angular momentum mixing between the SU(2) and SO(3) spins, mimicking the spin from isospin mechanism.

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arXiv2026

Moduli space of ${\cal N}=4$ Super Yang-Mills from AdS/CFT

We study ${\cal N}=4$ super Yang-Mills theory compactified on a circle at zero temperature, with VEVs for two scalar bilinears and three independent current sources. We show that type IIB supergravity provides a complete holographic description of this setup, admitting both supersymmetric and non-supersymmetric AdS soliton solutions, which are asymptotically AdS$_5$ and smooth in the IR. The current sources correspond in (2+1) dimensions to Q-ball charge densities for $U(1)^3\subset SO(6)_R$, and are geometrically realized as twists along three angular directions of the $S^5$. We demonstrate that the bulk dynamics encodes the full vacuum structure of the dual field theory and explicitly reconstruct the supersymmetric moduli space.

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arXiv2025

A Master Superspace Action for 3D S-Duality

We formulate a `master' partition function in three-dimensional $\mathcal{N}=2$ superspace that realises, upon integrating out complementary superfields, both the electric Maxwell--Chern--Simons (MCS) theory and its magnetic $S$-dual: a non-gauge Deser--Jackiw self-dual massive vector times a decoupled level-$k$ Chern--Simons term. The two descriptions share the topological mass $M=\frac{g^{2}k}{2π}$ and obey an exact partition-function identity $\mathcal Z_{\rm mag}(g_m^2,k)=\mathcal Z_{\rm ele}(g_e^2,k)$ with $g_e g_m=2π$, mapping a weakly coupled MCS theory to a strongly coupled Deser--Jackiw CS theory. Special limits reproduce pure Chern--Simons/Gaiotto--Witten ($g^{2}=0$) and Maxwell/compact-scalar duality ($k=0$). We extend the construction to a non-Abelian U$(N)$ gauge group obtaining $\mathcal N=2$ Yang--Mills--Chern--Simons on the electric side and a massive non-gauge vector coupled to level-$k$ Chern--Simons on the magnetic side; the interaction terms between the massive vector and the Chern-Simons term vanish in the Abelian case. Decomposing the $\mathcal N=2$ vector into an $\mathcal N=1$ vector and a real-linear multiplet factorises the master action and yields the $\mathcal N=1$ counterparts. This uplifts the bosonic duality formulated recently to $\mathcal N=2$ and clarifies its non-Abelian and $\mathcal N=1$ reductions.

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arXiv2025

Type II embeddings for $d=6$ Einstein-Maxwell gauged supergravity

Bi-spinor and G-structure methods are used to classify the possible consistent truncations of type II supergravity to $d=6$ Einstein-Maxwell (gauged) supergravity, and its consistent sub-sectors. In the absence of R-symmetry gauging and a tensor multiplet we establish that every supersymmetric Mink$_6$ solution defines an embedding of the $d=6$ theory. Adding a tensor multiplet places restrictions on these embeddings, but embeddings still exist. In the presence of R-symmetry gauging the internal spaces of the embeddings are neither related to Mink$_6$ or AdS$_6$. Under the assumption that the internal space contains a single U(1) isometry housing the $d=6$ gauge field we classify the possible embedding manifolds. We find two classes of embedding for the entire theory, one of which is governed by a Toda-like equation and contains at least one bounded embedding. In the absence of a tensor multiple the classes of embeddings become more permissive, though the PDEs governing them become more complicated in general.

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arXiv2025

Twisted-Circle Compactifications of SQCD-like Theories and Holography

We construct and analyse holographic duals to a class of four-dimensional N = 1 SU($N_c$) SQCD-like theories compactified on a circle with an R-symmetry twist. The setup originates from type IIB backgrounds previously proposed as duals to SQCD with $N_f$ fundamental flavours. The U(1) R-symmetry is anomaly-free only if $ N_f = 2N_c$. We implement a supersymmetric twisted-circle reduction, holographically realised through a smoothly shrinking $S^1$ fibered over the internal U(1)$_R$ direction. We obtain new regular type IIB supergravity backgrounds that are valid only if the condition $N_f = 2N_c$ is satisfied--mirroring the anomaly cancellation requirement in the field theory. We compute various field-theoretic observables--including the Chern-Simons level, Wilson loop and the holographic central charge--showing the emergence of a 3D ${\cal N} = 2$ gapped phase consistent with a Chern-Simons TQFT. This work highlights the interplay between anomalies, supersymmetry, and geometry in the holographic realisation of compactified gauge theories with fundamental matter.

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arXiv2025

A Note on Seiberg Duality for $N_{f} < N_{c}$

We consider SQCD for $N_{f}<N_{c}$. We use a brane configuration in type IIA string theory to propose a Seiberg dual. The brane configuration that realises the magnetic theory contains $N_{f}$ branes and $N_{c}-N_{f}$ \textit{anti}-branes, leading to an $SU(N_{c}-N_{f})$ gauge theory with $N_{f}$ flavours. The potential between the branes triggers a RG flow and we argue that the IR theory realises the Affleck-Dine-Seiberg superpotential. We use both field theory arguments, in particular anomaly matching, and a lift of the type IIA brane configuration to M-theory, in order to support our proposal.

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arXiv2024

Circle compactifications of Minkowski$_D$ solutions, flux vacua and solitonic branes

G-structure techniques are used to construct broad classes of circle compactifications of Mink$_{D+1}$ solutions to Mink$_{D}$ embedded into type II supergravity for $D=1,...5$. Under a certain assumptions we show that the conditions that imply supersymmetry for Mink$_{D+1}$ imply those of the Mink$_{D}$ solution, but that Bianchi identities of the fluxes must be modified. This realises an off shell solution generating technique for supersymmetric solutions or a "supersymmetry generating" technique. Along the way it is necessary for us to derive G structure conditions for general ${\cal N}=(1,0)$ supersymmetric Mink$_2$ solutions and a restricted class of Mink$_1$ solutions. We apply our results to construct some simple Minkowski flux vacua before turning our attention to "solitonic branes" which are generalisations of the AdS soliton. We are able to generalise known examples in two ways: 1) to embed them in terms of generic Sasaki Einstein manifolds. 2) To modify the harmonic factor to include D$p$ brane sources at one end of the space.

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arXiv2024

Twisted circle compactification of $\mathcal{N}=4$ SYM and its Holographic Dual

We consider a compactification of 4D $\mathcal{N}=4$ SYM, with $SU(N)$ gauge group, on a circle with anti-periodic boundary conditions for the fermions. We couple the theory to a constant background gauge field along the circle for an abelian subgroup of the $R$-symmetry which allows to preserve four supersymmetries. The 3D effective theory exhibits gapped and ungapped phases, which we argue are holographically dual, respectively, to a supersymmetric soliton in AdS$_{5}\times S^{5}$, and a particular quotient of AdS$_5\times S^5$. The gapped phase corresponds to an IR 3D $\mathcal{N}=2$ supersymmetric Yang-Mills-Chern-Simons theory at level $N$, while the ungapped phase is naturally identified with the root of a Higgs branch in the 3D theory. We discuss the extension of the twisting procedure to maximally SUSY Yang-Mills theories in different dimensions, obtaining the relevant duals for 2D and 6D, and comment on the odd dimensional cases.

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arXiv2024

Penrose limits of I-branes, twist-compactified D5-branes and spin chains

In this paper we consider the Penrose limit in the case of two gravity duals. One of them, consists of compactified I-branes (intersecting sets of D5-branes over $(1+1)$ dimensions). The second consists of D5-branes compactified on a circle. Both compactifications preserve SUSY. We find a match of the oscillators and masses of string modes on the resulting pp wave against a spin chain in a $(2+1)-$dimensional field theory in the first case, and a spin chain in a $(1+1)-$dimensional field theory in the second.

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arXiv2024

Confinement and D5 branes

In this work we present new solutions of type IIB supergravity based on wrapped D5 branes. We propose that two of these backgrounds are holographically dual to Quantum Field Theories that confine. The high energy regime of the field theories is that of a Little String Theory. We study various observables (Wilson and 't Hooft loops, Entanglement entropy, density of degrees of freedom and the spectrum of spin-two glueballs, among others). We also present two new black membrane backgrounds and analyse some thermodynamic aspects of these solutions.

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arXiv2023

Confinement in $(1+1)$ dimensions: a holographic perspective from I-branes

In this paper we holographically study the strongly coupled dynamics of the field theory on I-branes (D5 branes intersecting on a line). In this regime, the field theory becomes $(2 + 1)$ dimensional with 16 supercharges. The dual background has an IR singularity. We resolve this singularity by compactifying the theory on a circle, preserving 4 supercharges. We study various aspects: confinement, symmetry breaking, Entanglement Entropy, etc. We also discuss a black membrane solution and make some comments on the string $σ$-model on our backgrounds.

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arXiv2023

Compactification of 6d ${\cal N}=(1,0)$ quivers, 4d SCFTs and their holographic dual Massive IIA backgrounds

In this paper we study an infinite family of Massive Type IIA backgrounds that holographically describe the twisted compactification of ${\cal N}=(1,0)$ six-dimensional SCFTs to four dimensions. The analysis of the branes involved suggests a four dimensional linear quiver QFT, that deconstructs the theory in six dimensions. For the case in which the system reaches a strongly coupled fixed point, we calculate some observables that we compare with holographic results. Two quantities measuring the number of degrees of freedom for the flow across dimensions are studied.

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arXiv2023

Dualities of 3D $\mathcal{N}=1$ SQCD from Branes and non-SUSY deformations

We study the dynamics of an 'electric' $\mathcal{N}=1$ 3D $U(N_c)_{k,k+\frac{N_c}{2}}$ SQCD theory. By embedding the theory in string theory, we propose that the theory admits a 'magnetic' dual and analyse the low energy dynamics of the theory using its dual. When $\frac{N_f}{2} \ge\frac{N_c}{2}-k$ the IR dynamics is described by either a TQFT for large quark masses, or a Grassmanian and a Wess-Zumino (WZ) term for small masses. We also consider non-supersymmetric mass deformations and RG flows in the vicinity of the SUSY point and find agreement between the IR of the electric and its magnetic dual. When $\frac{N_f}{2} < \frac{N_c}{2}-k$ supersymmetry is broken and the IR dynamics is a described by a TQFT accompanied by a Goldstino. We also discuss SQCD theories based on $SO$/$USp$ gauge groups.

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arXiv2022

Comments on non-Abelian T-duals and their holographic description

We present three different Type IIB AdS$_4$ Supergravity solutions, derived using the electrostatic-like problem formalism which preserves 8 Poincaré Supercharges. Two of these solutions correspond to the Abelian and non-Abelian T-duals of a Type IIA background, obtained from the dimensional reduction of 11D AdS$_4 \times S^7$ Supegravity. The third solution is a new background with some special properties. We compute the Page charges in each case, and provide brane set-up descriptions of the geometries. Also, we argue that the non-Abelian T-dual can be understood as a zoom-in of a more general background with a well defined holographic dual.

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arXiv2021

Comments on single trace $T\bar{T}$ and other current-current deformations

String theory on AdS$_3$ with NS-NS fluxes admits a solvable irrelevant deformation which is close to the $T\bar{T}$ deformation of the dual CFT$_2$. This consists of deforming the worldsheet action, namely the action of the $SL(2,\mathbb{R})$ WZW model, by adding to it the operator $J^-\bar{J}^-$, constructed with two Kac-Moody currents. The geometrical interpretation of the resulting theory is that of strings on a conformally flat background that interpolates between AdS$_3$ in the IR and a flat linear dilaton spacetime with Hagedorn spectrum in the UV, having passed through a transition region of positive curvature. Here, we study the properties of this string background both from the point of view of the low-energy effective theory and of the worldsheet CFT. We first study the geometrical properties of the semiclassical geometry, then we revise the computation of correlation functions and of the spectrum of the $J^-\bar{J}^-$-deformed worldsheet theory, and finally we discuss how to extend this type of current-current deformation to other conformal models.

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arXiv2020

Quasinormal modes and black hole hairs in AdS

Holography relates the quasinormal modes frequencies of AdS black holes to the pole structure of the dual field theory propagator. These modes thus provide the timescale for the approach to thermal equilibrium in the CFT. Here, we study how such pole structure and, in particular, the time to equilibrium can get modified in the presence of a black hole hair. More precisely, we consider in AdS a set of relaxed boundary conditions that allow for a low decaying graviton mode near the boundary, which triggers an additional degree of freedom. We solve the scalar field response on such background analytically and non-perturbatively in the hair parameter, and we obtain how the pole structure gets affected by the presence of a black hole hair, relative to that of the usual AdS black hole geometry. The setup we consider is a massive 3D gravity theory, which admits a one-parameter family deformation of BTZ solution and enables us to solve the problem analytically. The theory also admits an AdS$_3$ soliton which gives a family of vacua that can be constructed from the hairy black hole by means of a double Wick rotation. The spectrum of normal modes on the latter geometry can also be solved analytically; we study its properties in relation to those of the AdS$_3$ vacuum.

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arXiv2020

Quadratic gravity and conformally coupled scalar fields

We construct black hole solutions in four-dimensional quadratic gravity, supported by a scalar field conformally coupled to quadratic terms in the curvature. The conformal matter Lagrangian is constructed with powers of traces of a conformally covariant tensor, which is defined in terms of the metric and a scalar field, and has the symmetries of the Riemann tensor. We find exact, neutral and charged, topological black hole solutions of this theory when the Weyl squared term is absent from the action functional. Including terms beyond quadratic order on the conformally covariant tensor, allows to have asymptotically de Sitter solutions, with a potential that is bounded from below. For generic values of the couplings we also show that static black hole solutions must have a constant Ricci scalar, and provide an analysis of the possible asymptotic behavior of both, the metric as well as the scalar field in the asymptotically AdS case, when the solutions match those of general relativity in vacuum at infinity. In this frame, the spacetime fulfils standard asymptotically AdS boundary conditions, and in spite of the non-standard couplings between the curvature and the scalar field, there is a family of black hole solutions in AdS that can be interpreted as localized objects. We also provide further comments on the extension of these results to higher dimensions.

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