arXiv subjects

Yolanda Lozano

Publications and source records attributed to Yolanda Lozano.

At least 19 recordsLinked to original sources

arXiv2025

Monodromy Defects in Massive Type IIA

In this paper we study solutions to massive Type IIA supergravity which we propose are dual to co-dimension 2 monodromy defects in 6d (1,0) CFTs realised in NS5-D6-D8 brane systems, as well as in the 5d Sp(N) fixed point theory. In the first case the defects are studied holographically as solutions to 7d $U(1)$ gauged supergravity that asymptote locally to its maximally supersymmetric $\text{AdS}_7$ vacuum away from the defects. In the second case they are dual to solutions to 6d $U(1)^2$ gauged supergravity that asymptote to its maximally supersymmetric $\text{AdS}_6$ vacuum. These solutions are then uplifted to massive Type IIA supergravity using known consistent truncations previously constructed in the literature. We compute the defect entanglement entropy and provide evidence that for the 3d defects, the entanglement entropy can be written as a linear combination of the free energy and conformal weight of the defect. Finally, we construct new co-dimension 2 monodromy defects in 6d and 5d CFTs compactified on Riemann surfaces and/or spindles.

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arXiv2025

Defect entanglement entropy for superconformal monodromy defects

We compute the defect entanglement entropy for co-dimension two superconformal monodromy defects in well known maximally symmetric holographic theories of various dimension. In each case we explicitly relate the universal part of the defect entanglement entropy to field theory data characterising the defect conformal field theory. We provide evidence that, unlike in the bulk theories in which the defects reside, the universal part of the defect entanglement entropy does not necessarily decrease along a renormalisation group flow.

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arXiv2025

On $\text{AdS}_2\times \text{S}^7$, its $\mathbb{Z}_k$ orbifold and their dual quantum mechanics

We consider a previously constructed class of massive Type IIA AdS$_2\times$S$^7\times I$ solutions with OSp$(8|2)$ symmetry, as well as OSp$(6|2)$-symmetric ones, by replacing the S$^7$ with the orbifold S$^7/\mathbb{Z}_k$. In both cases we construct global solutions for which the interval $I$ is bounded between physical singularities, by allowing D8-branes transverse to $I$. We also generate a new class of Type IIB AdS$_2\times \mathbb{CP}^3\times\text{S}^1\times I$ solutions by T-duality and establish a chain of dualities that maps the massless limit of these classes to AdS$_4/\mathbb{Z}_{k'}\times\text{S}^7/\mathbb{Z}_k$, thus identifying the brane configurations yielding these solutions. We propose that the ${\cal N}=8$ solutions are dual to a theory living on a D0-F1-D8 brane intersection which has a description in terms of disconnected quivers and similarly for the ${\cal N}=6$ solutions.

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arXiv2025

$\mathcal{N}=6$ supersymmetric AdS$_2 \times \mathbb{CP}^3\times Σ_2 $

We perform a complete classification of AdS$_2$ solutions of Type II supergravity realising $\mathcal{N}=6$ supersymmetry and OSp$(6|2)$ superconformal symmetry on backgrounds that are foliations of AdS$_2 \times \mathbb{CP}^3$ over a Riemann surface $Σ_2$. Such solutions only exist in type IIB supergravity and are in 1 to 1 correspondence with a fourth order PDE that can be locally solved in terms of two holomorphic functions. Particular solutions in the class are the T-duals of the $\text{AdS}_3\times \mathbb{CP}^3$ and $\text{AdS}_2\times \text{S}^7$ solutions to massive Type IIA supergravity found in the literature. We discuss the field theory interpretation of the two sub-classes of solutions related to $\text{AdS}_3\times \mathbb{CP}^3$ by Abelian and non-Abelian T-duality, which provide explicit examples for the Riemann surface an annulus or a strip. In the second case we interpret the solutions as holographic duals to baryon vertex configurations realised in D2-brane box models.

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arXiv2025

($0,6$) AdS$_3$/CFT$_2$ and surface defects

We explore a new class of AdS$_3$ solutions in massive type IIA supergravity preserving $\mathcal{N} = (0,6)$ supersymmetry and realising an $\mathfrak{osp}(6|2)$ superconformal algebra. These solutions exhibit an SO(6)-symmetric internal space constructed from a $\mathbb{CP}^3$, and are fully specified by a single cubic function controlling the fluxes and warping. We propose a brane box configuration underlying the solutions from which we construct a two-dimensional quiver gauge theory whose anomaly structure and central charge we analyse, and from which we can realise Seiberg-like dualities as large gauge transformations. The brane box configuration suggests an interpretation of the solutions as dual to surface defects within the ABJ(M) theory. Our findings provide a concrete setting for exploring holography beyond the ABJM vacuum. Remarkably, no explicit field theories are currently known to realise $\mathcal{N} = (0,6)$ supersymmetry in two dimensions, making our setup a promising and largely unexplored direction for field-theoretic investigations.

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arXiv2024

Half-BPS Janus solutions in AdS$_7$

We study half-BPS flows in gauged minimal 7d supergravity featured by an AdS$_3\times S^3$ slicing of the metric, supported by a dyonic three-form field. We first present a novel strategy for analytic integration of the BPS equations, which makes use of the integrals of motion. Subsequently, we discuss the suitable choice of integration constants that gives rise to smooth geometries. These flows are asymptotically locally AdS$_7$ in their UV limit, while their IR geometry is AdS$_3\times \mathbb{R}^4$. We then discuss their uplifts to 11d and massive IIA supergravity and observe that they describe one-parameter deformations of their AdS$_7\times S^4$ and AdS$_7\times S^3$ vacua, respectively, their holographic interpretation being as conformal defect CFT$_2$'s within the corresponding dual SCFT$_6$'s. We conclude with the computation of the holographic central charge, by focussing on the M-theory interpretation.

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arXiv2024

Deconstruction and surface defects in 6d CFTs

We study the two families of AdS$_3\times S^3\times S^2\times Σ_2$ solutions to massive Type IIA supergravity with small and large $(0,4)$ supersymmetries constructed recently in the literature, in connection with the AdS$_7\times S^2\times I$ solutions to massive Type IIA, to which they asymptote locally. Based on our analysis of various observables, that we study holographically, we propose an interpretation of the first class of solutions as dual to deconstructed 6d (1,0) CFTs dual to AdS$_7$, and of the second class as dual to surface defects in the same 6d theories. Among the observables that we study are baryon vertices and giant graviton configurations in quiver-like constructions.

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arXiv2024

Holographic $\frac{1}{2}$-BPS surface defects in ABJM

We study the class of $\text{AdS}_3\times \mathbb{CP}^3$ solutions to massive Type IIA supergravity with $\mathfrak{osp}(6|2)$ superconformal algebra recently constructed in arXiv:2304.12207 [hep-th]. These solutions are foliations over an interval preserving $\mathcal{N}=(0,6)$ supersymmetry in two dimensions, that in the massless limit can be mapped to the $\text{AdS}_4\times \mathbb{CP}^3$ solution of ABJM/ABJ. We show that in the massive case extra NS5-D8 branes, that we interpret as $\frac{1}{2}$-BPS surface defect branes within the ABJ theory, backreact in the geometry and turn one of the 3d field theory directions onto an energy scale, generating a flow towards a 2d CFT. We construct explicit quiver field theories that we propose flow in the IR to the $(0,6)$ SCFTs dual to the solutions. Finally, we show that the $\text{AdS}_3$ solutions realise geometrically, in terms of large gauge transformations, an extension to the massive case of Seiberg duality in ABJ theories proposed in the literature.

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arXiv2023

New $\text{AdS}_2/\text{CFT}_1$ pairs from $\text{AdS}_3$ and monopole bubbling

We present general results on generating $\text{AdS}_2$ solutions to Type II supergravity from $\text{AdS}_3$ solutions via U(1) and SL(2) T-dualities. We focus on a class of Type IIB solutions with small $\mathcal{N}=4$ supersymmetry, that we show can be embedded into a more general class of solutions obtained by double analytical continuation from $\text{AdS}_3$ geometries with small $\mathcal{N}=(0,4)$ supersymmetry constructed in the literature. We then start the analysis of the superconformal quantum mechanics dual to the $\mathcal{N}=4$ backgrounds focusing on a subclass of $\text{AdS}_2\times\text{S}^3\times\mathbb{T}^3$ solutions foliated over a Riemann surface. We show that the associated supersymmetric quantum mechanics describes monopole bubbling in 4d $\mathcal{N}=2$ supersymmetric gauge theories living in D3-D7 branes, as previously discussed in the literature. Therefore, we propose that our solutions provide a geometrical description via holography of monopole bubbling in 4d $\mathcal{N}=2$ SCFTs. We check our proposal with the computation of the central charge.

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arXiv2022

Line defects as brane boxes in Gaiotto-Maldacena geometries

We construct a new family of $\text{AdS}_2\times S^2\times S^2$ solutions to Type IIA supergravity with 4 supercharges acting with non-Abelian T-duality on the recent class constructed in arXiv:2107.12277. We focus on a particular solution in this class asymptoting locally to an $\text{AdS}_5$ Gaiotto-Maldacena geometry. This solution allows for a line defect interpretation within the 4d $\mathcal{N}=2$ SCFT dual to this geometry, that we study in detail. We show that the defect branes, consisting on a non-trivial intersection of D2-D4-NS5-F1 branes, can be interpreted as baryon vertices within the 4d $\mathcal{N}=2$ SCFT, whose backreaction gives rise to the $\text{AdS}_2$ solution. We construct the explicit quiver quantum mechanics that flows in the IR to the dual SCQM, and show that it can be embedded within the quiver CFT associated to the $\text{AdS}_5$ solution. The quiver quantum mechanics arises from a brane box set-up of D2-branes stretched between perpendicular NS5-branes, that we construct from the $\text{AdS}_2$ solution. We provide non-trivial checks of our proposed duality. Our construction provides one further example of the successful applications of non-Abelian T-duality to holography, in this case in providing a very non-trivial connection between $\text{AdS}_2$ solutions, line defects and brane boxes.

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arXiv2022

AdS$_2$ near-horizons, defects and string dualities

We construct a new family of $\text{AdS}_2\times S^3\times S^2$ solutions to Type IIB supergravity arising as near-horizon geometries of D1-F1-D3-D5-NS5-D7 brane intersections preserving 4 supersymmetries. We show that a subclass of these solutions asymptotes locally to the $\text{AdS}_6\times S^2\times Σ_2$ solution to Type IIB supergravity holographically dual to the five dimensional Sp(N) fixed point theory. This suggests that these solutions can be interpreted as D1-F1-D3 line defects within this CFT. Switching off the D7-branes, we act with $\text{SL}(2, \mathbb{R})$ to construct a second family of solutions that can be related to an $\text{AdS}_3\times S^3\times S^3$ class of M-theory backgrounds describing surface defects within the six dimensional (1,0) SCFT dual to $\text{AdS}_7/\mathbb{Z}_k\times S^4$. Finally, using non-Abelian T-duality we construct new classes of $\text{AdS}_2\times S^2\times S^2$ solutions to Type IIA supergravity with 4 supercharges and elaborate on their M-theory origin.

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arXiv2022

New AdS$_3$/CFT$_2$ pairs in massive IIA with $(0,4)$ and $(4,4)$ supersymmetries

We construct a new class of $\text{AdS}_3\times $S$^3\times $M$_4$ solutions of massive Type IIA supergravity with $(0,4)$ supersymmetries and SU(3) structure. We study in detail two subclasses of these solutions. The first subclass is when M$_4=$S$^2\times Σ_2$, with $Σ_2$ a 2d Riemann surface, and the geometry is foliated over the $Σ_2$. We interpret these solutions as duals to surface defect CFTs within the 6d $(1,0)$ CFTs dual to the $\text{AdS}_7\times$S$^2\times I$ solutions of massive IIA supergravity. The second subclass is when M$_4=\mathbb{T}^3\times I$ and the geometry is foliated over the interval. In this case supersymmetry is enhanced to $(4,4)$ in the massless limit, and the solutions are holographically dual to $(4,4)$ CFTs living in two dimensional D2-NS5-D4 Hanany-Witten brane set-ups. In turn, in the massive case the solutions find an interpretation as D2-D4 branes embedded in Type I' string theory. We construct explicit quiver gauge theories from the different brane set-ups that flow in the IR to the 2d dual CFTs dual to the solutions. We check the validity of our proposals with the matching between the field theory and holographic central charges.

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arXiv2022

N=(0,4) Black String Chains

We construct black string solutions in Type IIA supergravity arising from intersecting D2-D4-D6-NS5 branes in the presence of fractional D4-branes. The fractional D4-branes arise from D6-branes wrapping (collapsing) two-cycles in a Calabi--Yau two-fold. In the near horizon limit these solutions give rise to AdS$_3$ geometries preserving $\mathcal{N}=(0,4)$ supersymmetry and fall within the recent classification of \cite{Lozano:2019emq}. We interpret our solutions as describing chains of black strings stacked on top of each other along an interval. We construct 2d quiver CFTs dual to our solutions that reproduce the Bekenstein-Hawking entropy microscopically.

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arXiv2022

New results in AdS/CFT in low dimensions from massive Type IIA

We review recent developments in the study of the AdS/CFT correspondence in low dimensions, focusing on the construction of AdS$_3$/CFT$_2$ and AdS$_2$/CFT$_1$ dual pairs in massive Type IIA string theory. We start discussing the $\text{AdS}_3\times S^2\times \text{CY}_2\times I$ solutions to massive IIA supergravity with $\mathcal{N}=(0,4)$ supersymmetry constructed in 1908.09851. We review the 2d CFTs dual to these solutions, together with their defect interpretation as surface defects within 5d fixed point theories living in D4-D8 bound states. Next, we discuss the $\text{AdS}_2\times S^3\times \text{CY}_2\times I$ solutions with $\mathcal{N}=4$ supersymmetry constructed in 2011.13932. We discuss the superconformal quantum mechanics dual to these solutions, that we interpret in terms of line defects realised as D0-D4 baryon vertices in 5d Sp(N) fixed point theories. We review a particular example in this class of solutions, constructed through non-Abelian T-duality with respect to a non-compact isometry group, and discuss the possible embedding of a 3d black hole geometry constructed long ago via non-Abelian T-duality within this solution.

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arXiv2021

New AdS$_2$ supergravity duals of 4d SCFTs with defects

We construct new families of $\text{AdS}_2 \times S^2 \times S^2$ solutions with 4 supercharges in Type II supergravities. We show that subclasses of these solutions can be interpreted in terms of defect branes embedded in 4d $\mathcal{N} = 4 $ SYM, or orbifolds thereof. This is explicitly realised by showing that the solutions asymptote locally to $\text{AdS}_5 \times S^5/\mathbb{Z}_n$, in Type IIB, or its T-dual background, in Type IIA. The latter is a Gaiotto-Maldacena geometry realised on an intersection of D4 and NS5 branes. We extend the Type IIA solutions to include D6 branes, and interpret them as describing backreacted baryon vertices within 4d $\mathcal{N} = 2$ CFTs living in D4-NS5-D6 intersections. We propose explicit quiver quantum mechanics in which the defect branes play the role of colour branes, with the D4 branes of the D4-NS5-D6 intersection becoming flavour branes. These quivers are used to compute the degeneracies of the ground states of the dual super conformal quantum mechanics, that are shown to agree with the holographic expressions.

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arXiv2021

New advancements in AdS/CFT in lower dimensions

We review recent developments in the study of the AdS/CFT correspondence in lower dimensions. We start summarising the classification of AdS$_3\times$S$^2$ solutions in massive Type IIA supergravity with (0,4) supersymmetries, and the construction of their 2d dual quiver CFTs. These theories are the seed for further developments, that we review next. First, we construct a new class of AdS$_3$ solutions in M-theory that describe M-strings in M5-brane intersections. Second, we generate a new class of AdS$_2\times$S$^3$ solutions in massive IIA with 4 supercharges that we interpret as describing backreacted baryon vertices within the 5d $\mathcal{N}=1$ QFT living in D4-D8 branes. Third, we construct two classes of AdS$_2$ solutions in Type IIB. The first are dual to discrete light-cone quantised quantum mechanics living in null cylinders. The second class is interpreted as dual to backreacted baryon vertices within 4d $\mathcal{N}=2$ QFT living in D3-D7 branes. Explicit dual quiver field theories are given for all classes of solutions. These are used to compute the central charges of the CFTs, that are shown to agree with the holographic expressions.

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arXiv2021

New AdS$_2$ backgrounds and ${\cal N}=4$ Conformal Quantum Mechanics

We present a new infinite family of Type IIB backgrounds with an AdS$_2$ factor, preserving ${\cal N}=4$ SUSY. For each member of the family we propose a precise dual Super Conformal Quantum Mechanics (SCQM). We provide holographic expressions for the number of vacua (the "central charge"), Chern-Simons terms and other non-perturbative aspects of the SCQM. We relate the "central charge" of the one-dimensional system with a combination of electric and magnetic fluxes in Type IIB. The Ramond-Ramond fluxes are used to propose an extremisation principle for the central charge. Other physical and geometrical aspects of these conformal quantum mechanics are analysed.

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arXiv2021

$\text{AdS}_2\times \text{S}^2\times \text{CY}_2$ solutions in Type IIB with 8 supersymmetries

We present a new infinite family of Type IIB supergravity solutions preserving eight supercharges. The structure of the space is $\text{AdS}_2\times\text{S}^2\times \text{CY}_2\times \text{S}^1$ fibered over an interval. These solutions can be related through double analytical continuations with those recently constructed in \cite{Lozano:2020txg}. Both types of solutions are however dual to very different superconformal quantum mechanics. We show that our solutions fit locally in the class of $\text{AdS}_2\times \text{S}^2\times \text{CY}_2$ solutions fibered over a 2d Riemann surface $Σ$ constructed by Chiodaroli, Gutperle and Krym, in the absence of D3 and D7 brane sources. We compare our solutions to the global solutions constructed by Chiodaroli, D'Hoker and Gutperle for $Σ$ an annulus. We also construct a cohomogeneity-two family of solutions using non-Abelian T-duality. Finally, we relate the holographic central charge of our one dimensional system to a combination of electric and magnetic fluxes. We propose an extremisation principle for the central charge from a functional constructed out of the RR fluxes.

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