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Niall T. Macpherson

Publications and source records attributed to Niall T. Macpherson.

At least 19 recordsLinked to original sources
arXiv2026

Supersymmetric $\mathbb{WCP}^n$, AdS near horizons and orbifolds

We construct and study the supersymmetry properties of the weighted projective spaces $\mathbb{WCP}^2$ and $\mathbb{WCP}^3$. These are topologically $\mathbb{CP}^n$ with $n+1$ orbifold singularities and as such are higher dimensional analogues of the ``spindle'' or $\mathbb{WCP}^1$. We use these to construct interesting supersymmetric orbifolds of canonical near horizon geometries of relevance to the AdS/CFT correspondence. Interestingly, for certain tunings of their integer weights, and unlike the spindle, $\mathbb{WCP}^{2}$ and $\mathbb{WCP}^{3}$ are compatible with supersymmetry beyond the realm of gauged supergravity. This allows one to construct interesting supersymmetric solutions in type II supergravity such as AdS$_5\times\mathbb{WCP}^{2}\times\text{S}^1$ and AdS$_4\times \mathbb{WCP}^3$ via duality, in which $\mathbb{WCP}^n$ appears without a connection fibred over it. We also leverage our results to construct a supersymmetric AdS$_3$ solution containing a topological $\mathbb{T}^{(1,1)}$ space with 4 orbifold singularities.

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arXiv2026

M5 branes wrapping $\mathbb{WCP}^2$ and spindles fibred over constant curvature Riemann surfaces

We classify AdS$_3$ solutions of the U(1) invariant sector of minimal $d=7$ supergravity. We find two classes of solutions preserving ${\cal N}=(2,0)$ supersymmetry for which the internal space M$_4$ is either a negative curvature Kahler-Einstein manifold or a circle fibration over $Σ\times \mathbb{R}$. For the later, in the case that $Σ$ has constant curvature, we reduce finding a solution to solving a single ODE that admits polynomial solutions. Among these are interesting solutions whose uplifts to $d=11$ describe M5 branes wrapping various $d=4$ orbifolds. These include a topological $\mathbb{CP}^2$ with 2 orbifold fixed points that we identify as the weighted projective space $\mathbb{WCP}^2_{[k,k,\ell]}$. We are also able to construct solutions with M5 branes that wrap a spindle fibred over constant curvature Riemann surfaces of arbitrary genus. Such solutions should provide holographic duals to the ${\cal N}=(2,0)$ SCFT associated to the M5 brane compactified to $d=2$ on these orbifolds. We match the holographic central charges of these solutions to a field theory computation in terms of anomaly polynomials and c-extremisation.

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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

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

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

${\cal N}=(4,4)$ supersymmetric AdS$_3$ solutions in $d=11$

We derive necessary and sufficient conditions for AdS$_3$ solutions of $d=11$ supergravity to preserve ${\cal N}=(1,1)$ supersymmetry in terms of G-structures. Such solutions necessarily support an SU(3)-structure on the internal 8-manifold M$_8$, in terms of which we phrase the conditions for supersymmetry preservation. We use this to derive the local form of all ${\cal N}=(4,4)$ supersymmetric AdS$_3$ solutions in $d=11$, for which M$_8$ decomposes as a foliation of a 3-sphere over a 5 dimensional base. There are 3 independent classes, 2 of which preserve the small superconformal algebra and one preserving its large counterpart for which M$_5$ contains a second 3-sphere. We show that for each solution with large (4,4) supersymmetry there are two corresponding solutions with small $(4,4)$, one for which M$_5$ maintains its 3-sphere, one where this blows up to $\mathbb{R}^3$ which can be compactified to $\mathbb{T}^3$. We use our results to construct several new solutions that lie within our derived classes as well as recovering some existing solutions.

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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

Marginally deformed AdS$_5$/CFT$_4$ and spindle-like orbifolds

We study marginal deformations of ${\cal N}=2$, $d=4$ long linear quiver CFTs using the holographic description. We find a two-parameter family of AdS$_5$ solutions that generically break all of supersymmetry, but preserve ${\cal N}=1$ for a particular tuning of the parameters. We study the G-structure of the ${\cal N}=2$ "parent" and the ${\cal N}=1$ backgrounds and carefully discuss the quantisation of charges in all cases. For the ${\cal N}=1$ and ${\cal N}=0$ cases, a picture emerges with "branes" back-reacted on either a spindle or its higher dimensional analogue. Comments on the marginally deformed dual CFTs are given, together with the study of some observables.

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arXiv2024

G-structures for black hole near-horizon geometries

We derive necessary and sufficient conditions for warped AdS$_2$ solutions of Type II supergravity to preserve ${\cal N}=1$ supersymmetry, in terms of bispinors. Such solutions generically support an SU$(3)$-structure on their internal manifold M$_8$, which can experience an enhancement to a G$_2$-structure. We perform an SU$(3)$-structure torsion classes analysis and express the fluxes and other physical fields in terms of these, in general. We use our results to derive two new classes of AdS$_2$ solutions. In (massive) Type IIA supergravity we derive an ${\mathcal N}=1$ supersymmetric class for which M$_8$ decomposes as a weak G$_2$-manifold foliated over an interval and which is locally defined in terms of a degree three polynomial. In Type IIB supergravity we find a class of AdS$_2\times\text{S}^2\times\text{CY}_2\timesΣ_2$ solutions preserving small ${\cal N}=4$ supersymmetry, governed by a harmonic function on $Σ_2$ and partial differential equations reminiscent of D3-D7-brane configurations.

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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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arXiv2024

On Type IIA AdS$_3$ solutions and massive GK geometries

We give the necessary and sufficient conditions for warped AdS$_3$ (and Mink$_3$) solutions of Type II supergravities to preserve ${\cal N}=(2,0)$ supersymmetry, in terms of geometric conditions on their internal space M$_7$. Such solutions possess a canonical ten-dimensional Killing vector that can be either time-like or null. In this work we classify the null case in massive Type IIA supergravity which necessitates that M$_7$ decomposes as a circle fibration over a six-dimensional base with orthogonal SU(2)-structure containing a complex four-manifold. We narrow our focus to solutions for which M$_7$ becomes $\mathbb{T}^2$ fibred over a foliation of a Kähler manifold over an interval. We find a class of solutions which are the massive Type IIA version of GK geometries and present an extremal problem which computes the central charge of the solution using just topology. Finally, we present geometric conditions for AdS$_3$ solutions to preserve arbitrary extended chiral supersymmetry.

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arXiv2023

AdS$_3$ vacua realising $\mathfrak{osp}(n|2)$ superconformal symmetry

We consider ${\cal N}=(n,0)$ supersymmetric AdS$_3$ vacua of type II supergravity realising the superconformal algebra $\mathfrak{osp}(n|2)$ for $n>4$. For the cases $n=6$ and $n=5$, one can realise these algebras on backgrounds that decompose as foliations of AdS$_3\times \mathbb{CP}^3$ ( squashed $\mathbb{CP}^3$ for $n=5$) over an interval. We classify such solutions with bi-spinor techniques and find the local form of each of them: They only exist in (massive) IIA and are defined locally in terms of an order 3 polynomial $h$ similar to the AdS$_7$ vacua of (massive) IIA. Many distinct local solutions exist for different tunings of $h$ that give rise to bounded (or semi infinite) intervals bounded by physical behaviour. We show that it is possible to glue these local solutions together by placing D8 branes on the interior of the interval without breaking supersymmetry, which expands the possibilities for global solutions immensely. We illustrate this point with some simple examples. Finally we also show that AdS$_3$ vacua for $n=7,8$ only exist in $d=11$ supergravity and are all locally AdS$_4\times$S$^7$.

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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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arXiv2023

A plethora of Type IIA embeddings for $d=5$ minimal supergravity

We construct multiple embeddings of all solutions of $d=5$ minimal (un)gauged supergravity into massive Type IIA supergravity. The internal spaces and warpings of such embeddings are the same as those of the $\mathcal{N}=1$ supersymmetric (Mink$_5$) AdS$_5$ vacua, with the slight modification that the U(1) R-symmetry direction becomes fibered over the external space by the $d=5$ gauge field. In addition the fluxes are appropriately modified. There are many distinct types of the aforementioned internal spaces and as such many different embeddings of the $d=5$ supergravity. As examples of our setup we provide new solutions dual to six-dimensional, $\mathcal{N}=(1,0)$ SCFTs compactified on the product of a constant curvature Riemann surface and a spindle. We also provide a multitude of massive Type IIA embeddings for rotating, asymptotically AdS$_5$ black hole solutions.

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arXiv2022

On generalised D1-D5 near horizons and their spectra

There has been considerable recent interest in type II string compactifications on AdS$_3\times$S$^3\times$M$_{4}$ due to both new progress in the AdS$_3$/CFT$_2$ correspondence and an independent search for new ${\cal N}=(4,0)$ supergravity solutions. In this work we report a new family of small ${\cal N}=(4,0)$ preserving warped AdS$_3\times$S$^3\times $CY$_2$ compactifications of type IIB supergravity. The S$^3$ in this family is non trivially fibered over the CY$_2$. We show how these new solutions provide a IIB embedding of minimal ungauged $d=5$ supergravity coupled to an Abelian vector multiplet. We also make a few initial steps towards the identification of dual CFT$_2$ candidates. Specifically, we study the Kaluza-Klein spectrum of the spin two and certain vector fluctuations that are expected to be dual to the stress-energy tensor, SU(2) R current and several other BPS operator families in the dual CFT$_2$.

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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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