arXiv subjects

Oscar Varela

Publications and source records attributed to Oscar Varela.

At least 19 recordsLinked to original sources

arXiv2026

Maximal $D=5$ trombone supergravity from M5-branes and $\mathrm{SU}(2)$-flavoured $\mathcal{N}=1$ class $\mathcal{S}$ operator spectra

We recently presented a new $D=5$ $\mathcal{N}=8$ gauged supergravity involving the local trombone scaling symmetry. It arises by consistent truncation of M-theory on the internal space of the Maldacena-Núñez AdS$_5$ solution dual to the $\mathcal{N}=2$ four-dimensional superconformal field theory (SCFT) of class $\mathcal{S}$ associated to M5-branes wrapped on an unpunctured Riemann surface. Using exceptional generalised geometry/field theory, we extend that construction to show that the same $D=5$ $\mathcal{N}=8$ supergravity also arises by consistent truncation of $D=11$ supergravity on the family of $\mathcal{N}=1$ M5-brane-wrapped solutions of Bah-Beem-Bobev-Wecht, including the $\mathcal{N}=1$ Maldacena-Núñez (MN1) configuration. Then, using recently derived mass matrices, we compute universal sectors of the Kaluza-Klein spectrum on the MN1 solution. In general, this universal spectrum is only locally defined, and we give a prescription for extracting globally defined subsectors thereof. This globally defined universal Kaluza-Klein spectrum is dual to a universal sector of the light operator spectrum of the SU(2)-flavoured $\mathcal{N}=1$ class $\mathcal{S}$ SCFT dual to MN1.

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arXiv2026

Kaluza-Klein trombone mass matrices and universal class $\mathcal{R}$ operator spectra

We determine universal sectors of the light operator spectrum that are present in all A$_{N-1}$ superconformal field theories $T_N[Σ_3]$ of class $\mathcal{R}$, with $Σ_3$ a compact hyperbolic three-manifold. We do this at large $N$ by holographically mapping the problem to a Kaluza-Klein spectral analysis over previously known dual anti-de Sitter backgrounds related to wrapped M5-brane configurations. Associated to these, $D=4$ $\mathcal{N}=8$ supergravities have been recently constructed that allow for the application of spectral techniques based on exceptional generalised geometry/field theory. We derive the Kaluza-Klein mass matrices that arise when the seed lower-dimensional maximal supergravity involves gaugings of the trombone scaling symmetry, as pertains to the case at hand, and diagonalise them to find the universal Kaluza-Klein states. In general, these universal spectra are only defined locally, and we give a prescription to isolate globally-defined sectors therein.

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arXiv2026

Maximal trombone supergravity from wrapped M5-branes

A new family of maximal supergravities in four dimensions, involving gaugings of the trombone scaling symmetry, has been recently introduced. Using exceptional generalised geometry, we show some supergravities in this class to arise by consistent truncation of $D=11$ supergravity. The seven-dimensional reduction manifold is locally equivalent to the topologically-twisted internal manifold of the AdS$_4$ geometries that arise near the horizon of M5-branes wrapped on supersymmetric three-cycles of special holonomy manifolds. The dimensional reduction involves a mixture of conventional and generalised Scherk-Schwarz prescriptions, and provides the first maximally supersymmetric consistent truncation to four dimensions in the context of the M5-brane.

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arXiv2026

Consistent subsectors of maximal supergravity and wrapped M5-branes

A new family of $D=4$ $\mathcal{N}=8$ gauged supergravities is introduced, consisting in a mixture of Scherk-Schwarz and dyonic CSO gaugings that involves the trombone scaling symmetry. A specific theory in this class is shown to admit supersymmetric anti-de Sitter vacua, argued to be related to various wrapped M5-brane configurations. The mass spectrum of these vacua within our maximal theory is computed, extending previous results in smaller gauged supergravity models, and shown to exhibit some exotic features due to the trombone gauging. These vacua are obtained as solutions of certain subsectors of our $\mathcal{N}=8$ supergravity. Such subsectors in turn arise by consistent truncation of the parent maximal supergravity to the invariant fields under specific groups that are not contained in the $\mathcal{N}=8$ gauge group. Prompted by these and other similar subtruncations recently considered, we formalise sufficient conditions that allow any maximal supergravity to be truncated consistently to invariant subsectors thereof when the invariance group is not necessarily contained in the $\mathcal{N}=8$ gauge group.

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arXiv2026

Trombone gaugings of five-dimensional maximal supergravity

The maximal gauged supergravities in five spacetime dimensions with gauge groups contained in $\mathbb{R}^+ \times \textrm{E}_{6(6)}$ are described. The $\textrm{E}_{6(6)}$ factor is the duality group of ungauged maximal supergravity and $\mathbb{R}^+$ is the scaling symmetry of the five-dimensional metric, usually called the \textit{trombone} symmetry. The equations of motion and supersymmetry variations for these supergravities are given to lowest order in fermions, and the mass matrices are provided. Then, the theories with gauge groups contained in a maximal subgroup of $\mathbb{R}^+ \times \textrm{E}_{6(6)}$ are classified, and a new family of such supergravities uncovered. For a concrete theory in this class, some supersymmetric anti-de Sitter vacua are found and their mass spectra computed within the gauged supergravity. These vacua are argued to be related to superconformal phases of the M5-brane field theory.

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arXiv2025

Class $\mathcal{S}$ superconformal indices from maximal supergravity

We present a new gauging of maximal supergravity in five spacetime dimensions with gauge group containing ISO(5), involving the local scaling symmetry of the metric, and admitting a supersymmetric anti-de Sitter vacuum. We show this maximal supergravity to arise by consistent truncation of M-theory on the (non-spherical, non-parallelisable) six-dimensional geometry associated to a stack of $N$ M5-branes wrapped on a smooth Riemann surface. The existence of this truncation allows us to holographically determine the complete, universal spectrum of light operators of the dual four-dimensional $\mathcal{N}=2$ theory of class $\mathcal{S}$. We then compute holographically the superconformal index of the dual field theory at large-$N$, finding perfect agreement with previously known field theory results in specific limits.

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arXiv2024

Infinite and finite consistent truncations on deformed generalised parallelisations

Given a manifold $\mathbb{M}$ admitting a maximally supersymmetric consistent truncation, we show how to formulate new consistent truncations by restricting to a set of Kaluza-Klein modes on $\mathbb{M}$ invariant under some subgroup of the group of isometries of $\mathbb{M}$. These truncations may involve either finite or infinite sets of modes. We provide their global description using exceptional generalised geometry to construct a `deformed' generalised parallelisation starting with that on $\mathbb{M}$. This allows us to explicitly embed known consistent truncations directly into exceptional generalised geometry/exceptional field theory, and to obtain the equations governing situations where the consistent truncation retains an infinite tower of modes.

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arXiv2024

Kerr Effective Black Hole Geometries in Supergravity

We derive the explicit embedding of the effective Kerr spacetimes, which are pertinent to the vanishing of static Love numbers, soft hair descriptions of Kerr black holes, and low-frequency scalar-Kerr scattering amplitudes, as solutions within N = 2 supergravity. These spacetimes exhibit a hidden $SL(2, R) \times U (1)$ or $SO(4, 2)$ symmetry resembling the so called subtracted geometries with $SL(2, R) \times SL(2, R)$ symmetry, which accurately represent the near-horizon geometry of Kerr black holes and, as we will argue most accurately represents the internal structure of the Kerr black hole. To quantify the differences among the effective Kerr spacetimes, we compare their physical quantities, internal structures, and geodesic equations. Although their thermodynamic properties, including entropy, match those of Kerr, our study uncovers significant differences in the interiors of these effective Kerr solutions. A careful examination of the internal structure of the spacetimes highlights the distinctions between various effective Kerr geometries and their quasinormal spectra.

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arXiv2024

Supersymmetric spectroscopy on AdS$_4\times S^7$ and AdS$_4\times S^6$

New techniques based on Exceptional Field Theory have recently allowed for the calculation of the Kaluza-Klein spectra of certain AdS$_4$ solutions of $D=11$ and massive IIA supergravity. These are the solutions that consistently uplift on $S^7$ and $S^6$ from vacua of maximal four-dimensional supergravity with SO(8) and ISO(7) gaugings. In this paper, we provide the complete Kaluza-Klein spectrum of five such AdS$_4$ solutions, all of them ${\cal N}=1$. These solutions preserve SO(3) and $\textrm{U}(1) \times \textrm{U}(1)$ internal symmetry in $D=11$, and U(1) (two of them) and no continuous symmetry in type IIA. Together with previously discussed cases, our results exhaust the Kaluza-Klein spectra of known supersymmetric AdS$_4$ solutions in $D=11$ and type IIA in the relevant class.

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arXiv2022

$\mathcal{N}=1$ S-fold spectroscopy

We analyse the spectrum of Kaluza-Klein excitations above three distinct families of ${\cal N}=1$ AdS$_4$ solutions of type IIB supergravity of typically non-geometric, S-fold type that have been recently found. For all three families, we provide the complete algebraic structure of their spectra, including the content of OSp$(4|1)$ multiplets at all Kaluza-Klein levels and their charges under the residual symmetry groups. We also provide extensive results for the multiplet dimensions using new methods derived from exceptional field theory, including complete, analytic results for one of the families. All three spectra show periodicity in the moduli that label the corresponding family of solutions. Finally, the compactness of these moduli is verified in some cases at the level of the fully-fledged type IIB uplifted solutions.

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arXiv2021

The spectrum of marginally-deformed ${\cal N} = 2$ CFTs with AdS$_4$ S-fold duals of type IIB

A holographic duality was recently established between an ${\cal N} =4$ non-geometric AdS$_4$ solution of type IIB supergravity in the so-called S-fold class, and a three-dimensional conformal field theory (CFT) defined as a limit of ${\cal N} =4$ super-Yang-Mills at an interface. Using gauged supergravity, the ${\cal N} =2$ conformal manifold (CM) of this CFT has been assessed to be two-dimensional. Here, we holographically characterise the large-$N$ operator spectrum of the marginally-deformed CFT. We do this by, firstly, providing the algebraic structure of the complete Kaluza-Klein (KK) spectrum on the associated two-parameter family of AdS$_4$ solutions. And, secondly, by computing the ${\cal N} =2$ supermultiplet dimensions at the first few KK levels on a lattice in the CM, using new exceptional field theory techniques. Our KK analysis also allows us to establish that, at least at large $N$, this ${\cal N} =2$ CM is topologically a non-compact cylindrical Riemann surface bounded on only one side.

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arXiv2021

Super-Chern-Simons spectra from Exceptional Field Theory

Exceptional Field Theory has been recently shown to be very powerful to compute Kaluza-Klein spectra. Using these techniques, the mass matrix of Kaluza-Klein vector perturbations about a specific class of AdS$_4$ solutions of $D=11$ and massive type IIA supergravity is determined. These results are then employed to characterise the complete supersymmetric spectrum about some notable ${\cal N}=2$ and ${\cal N}=3$ AdS$_4$ solutions in this class, which are dual to specific three-dimensional superconformal Chern-Simons field theories.

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arXiv2020

Kaluza-Klein fermion mass matrices from Exceptional Field Theory and ${\cal N} =1$ spectra

Using Exceptional Field Theory, we determine the infinite-dimensional mass matrices for the gravitino and spin-$1/2$ Kaluza-Klein perturbations above a class of anti-de Sitter solutions of M-theory and massive type IIA string theory with topologically-spherical internal spaces. We then use these mass matrices to compute the spectrum of Kaluza-Klein fermions about some solutions in this class with internal symmetry groups containing SU(3). Combining these results with previously known bosonic sectors of the spectra, we give the complete spectrum about some ${\cal N}=1$ and some non-supersymmetric solutions in this class. The complete spectra are shown to enjoy certain generic features.

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arXiv2020

A Cubic Deformation of ABJM: The Squashed, Stretched, Warped, and Perturbed Gets Invaded

A superpotential deformation that is cubic in one of the chiral superfields of ABJM makes the latter theory flow into a new, ${\cal N}=2$ superconformal phase. This is holographically dual to a warped $\textrm{AdS}_4 \times_w S^7$ solution of M-theory equipped with a squashed and stretched metric on $S^7$. We determine the spectrum of spin-2 operators of the cubic deformation at low energies by computing the spectrum of Kaluza-Klein (KK) gravitons over the dual AdS$_4$ solution. We calculate, numerically, the complete graviton spectrum and, analytically, the spectrum of gravitons that belong to short multiplets. We also use group theory to assess the structure of the full KK spectrum, and conclude that ${\cal N}=2$ supermultiplets cannot be allocated KK level by KK level. This phenomenon, usually referred to as "space invaders scenario", is also known to occur for another $\textrm{AdS}_4$ solution based on a different squashed $S^7$.

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arXiv2020

Brane-jet stability of non-supersymmetric AdS vacua

We classify the non-supersymmetric, and perturbatively stable within $D=4$, AdS vacua of maximal $D=4$ supergravity with a dyonic ISO(7) gauging in a large sector of the supergravity. Seven such vacua are established within this sector, all of them giving rise to non-supersymmetric $\textrm{AdS}_{4} \times \textrm{S}^{6}$ type IIA backgrounds with and without non-trivial warpings and with internal fluxes. Then, we analyse the dynamics of various probe D$p$-branes in these backgrounds searching for potential brane-jet instabilities. In all these cases, such instabilities are absent. Finally, an alternative decay channel through tunnelling is investigated, focusing on one of the seven backgrounds. We do not find instabilities either, but the analysis remains inconclusive.

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arXiv2020

Flowing to $\mathcal{N}=3$ Chern--Simons-matter theory

New renormalisation group flows of three-dimensional Chern--Simons theories with a single gauge group $\textrm{SU}(N)$ and adjoint matter are found holographically. These RG flows have an infrared fixed point given by a CFT with $\mathcal{N}=3$ supersymmetry and $\text{SU}(2)$ flavour symmetry. The ultraviolet fixed point is again described by a CFT with either $\mathcal{N}=2$ and $\text{SU}(3)$ symmetry or $\mathcal{N}=1$ and $\text{G}_{2}$ symmetry. The gauge/gravity duals of these RG flows are constructed as domain-wall solutions of a gauged supergravity model in four dimensions that enjoys an embedding into massive IIA supergravity. A concrete RG flow that brings a mass deformation of the $\mathcal{N}=2$ CFT into the $\mathcal{N}=3$ CFT at low energies is described in detail.

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arXiv2020

Universal properties of Kaluza-Klein gravitons

Vacua of different gaugings of $D=4$ ${\cal N}=8$ supergravity that preserve the same supersymmetries and bosonic symmetry tend to exhibit the same universal mass spectrum within their respective supergravities. For AdS$_4$ vacua in gauged supergravities that arise upon consistent truncation of string/M-theory, we show that this universality is lost at higher Kaluza-Klein levels. However, universality is still maintained in a milder form, as certain sums over a finite number of states remain universal. Further, we derive a mass matrix for Kaluza-Klein gravitons which is valid for all the AdS$_4$ vacua in string/M-theory that uplift from the gaugings of $D=4$ ${\cal N}=8$ supergravity that we consider. The mild universality of mass sums is related to the trace of this mass matrix.

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arXiv2019

Halving ISO(7) supergravity

Half-maximal, $\,\mathcal{N}=4\,$, sectors of $\,D=4\,$ $\,\mathcal{N}=8\,$ supergravity with a dyonic ISO(7) gauging are investigated. We focus on a half-maximal sector including three vector multiplets, that arises as a certain $\,\textrm{SO}(3)_{\textrm{R}}$-invariant sector of the full theory. We discuss the embedding of this sector into the largest half-maximal sector of the $\,\mathcal{N}=8\,$ supergravity retaining six vector multiplets. We also provide its canonical $\,\mathcal{N}=4\,$ formulation and show that, from this perspective, our model leads in its own right to a new explicit gauging of $\,\mathcal{N}=4\,$ supergravity. Finally, expressions for the restricted duality hierarchy are given and the vacuum structure is investigated. Five new non-supersymmetric AdS vacua are found numerically. The previously known $\,\mathcal{N}=2\,$ and $\,\mathcal{N}=3\,$ AdS vacua are also contained in our $\,\mathcal{N}=4\,$ model. Unlike when embedded in previously considered sectors with fewer fields, these vacua exhibit their full $\,\mathcal{N}=2\,$ and $\,\mathcal{N}=3\,$ supersymmetry within our $\,\mathcal{N}=4\,$ model.

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