arXiv subjects

Riccardo Comi

Publications and source records attributed to Riccardo Comi.

13 recordsLinked to original sources

arXiv2026

Algorithmic Dualization of Unitary Circular Quivers

We introduce a field-theoretic algorithm to find the $SL(2,\mathbb{Z})$ duality web of 3d $\mathcal{N}=4$ circular quiver theories with unitary gauge groups, extending the algorithm for linear quivers. Although circular and linear quivers share the same local structure, the circular topology requires additional ingredients, which we formulate in terms of topological and baryonic QFT blocks, together with new $SL(2,\mathbb{Z})$ duality moves acting on them. For good circular quivers, this provides a field-theoretic derivation of mirror symmetry and extends it to the full $SL(2,\mathbb{Z})$ duality web. We then study bad circular quivers, distinguishing between local badness, associated with under-balanced gauge nodes, and global badness, arising from the circular topology itself. In particular, we analyze the magnetic and electric dual frames of globally bad circular quivers and provide additional evidence for the proposed duality by matching the Higgs branch index with the dual Coulomb branch index. The latter exhibits a structure reminiscent of permutation-group gauging and reveals a refined relation to the ADHM quiver, flowing to the $\mathcal{N}=8$ infrared fixed point.

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arXiv2026

Half-BPS Boundaries and the RG-Wall of $\mathcal{N}=2$ $SU(N)$ SYM

We identify the 3d theory that realizes the RG-wall interface of 4d $\mathcal{N}=2$ $SU(N)$ Super-Yang-Mills, interpolating between the UV Lagrangian and the IR Seiberg-Witten effective description. The same theory also describes the low-energy boundary condition that corresponds to giving half-BPS Dirichlet boundary condition in the Lagrangian description of 4d $\mathcal{N}=2$ $SU(N)$ SYM. The theory is a 3d $\mathcal{N}=2$ SCFT that can be obtained as a massive deformation of the $T[SU(N)]$ theory, which is the S-duality interface of 4d $\mathcal{N}=4$ $SU(N)$ SYM. As the main validating tests, we match half-indices and discuss non-trivial consistency conditions when colliding such interfaces.

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arXiv2026

Universal Planar Abelian Duals for 3d $\mathcal{N}=2$ Unitary CS-SQCD

We provide an explicit planar Abelian dual for three-dimensional $\mathcal{N}=2$ $U(N)_k$ SQCD with $F$ fundamental chiral multiplets. This construction covers the entire $(N, F, k)$ parameter space (provided supersymmetry is unbroken), offering a unified framework for the infrared physics of these theories. Our results generalize a recently discovered class of chiral-planar dualities, which were previously limited to the locus $F = 2|k| + 2N$, which is a mass deformation of $\mathcal{N}=4$ mirror symmetry plus a restricted set of additional mass deformations. By developing a systematic algorithm to track the flow of the dual theory under generic mass deformations, we establish the planar Abelian quiver not merely as a specific dual description, but as a universal tool for analyzing 3d gauge dynamics.

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arXiv2026

Limits of the Superconformal Index and the Moduli Space of 3d $\mathcal{N}=3$ Theories

We compute the Hilbert series of three-dimensional $\mathcal{N}=3$ quiver gauge theories by taking a specific limit of the superconformal index. Our approach introduces auxiliary fugacities associated with symmetries which, while not present in the full theory, arise as effective symmetries on specific branches of the moduli space. By evaluating the index in a limit governed by these parameters, we successfully isolate the Hilbert series of the desired branches. We validate our results against the literature and provide several new extensions. We focus primarily on linear and circular quivers with unitary gauge groups, which originate from Type IIB brane configurations involving generic $(p,q)$ fivebranes. We further generalise this approach to star-shaped and orthosymplectic $\mathcal{N}=3$ quivers. Finally, we investigate the geometric branches of affine Dynkin quivers, demonstrating agreement with known results, while offering new predictions for unexplored cases.

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arXiv2025

Breaking bad theories of class $\mathcal S$

We study weakly-coupled descriptions/channel decompositions of the 4d $\mathcal{N}=2$ theories of class $\mathcal{S}$ of type $\mathfrak{su}(N)$, from the perspective of the 3d $\mathcal{N}=4$ mirror duals of their circle compactifications. This is a delicate problem when the channel decomposition produces pathological, or bad, 4d configurations that correspond to spheres with non-maximal punctures. The star-shaped quivers, describing the 3d mirrors associated with such bad 4d configurations, are bad 3d $\mathcal{N}=4$ theories. Leveraging recent results regarding 3d bad theories, we identify a new and interesting family of bad theories, which we coin \textit{broken} theories, that naturally arise in this context. Using these broken theories, we develop a systematic and analytic method that determines the generically non-Lagrangian matter sectors and the weakly-coupled gauge groups in such channel decompositions. We understand these weakly-coupled descriptions as emerging dynamically via Higgs mechanisms triggered by operators acquiring vacuum expectation values.

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arXiv2025

Planar Abelian Duals of Chern-Simons QCD

We propose novel infrared dualities connecting 2+1 dimensional non-Abelian gauge theories (with unitary or special unitary gauge groups) to Abelian gauge theories. The dual Abelian theories are characterized by a planar quiver structure, where interactions are fully encoded in the quiver diagram. These dualities are rooted in supersymmetric mirror symmetry and display the characteristic exchange of mesonic and monopole operators. Furthermore, our proposed dualities exhibit features of bosonization: the addition of a fermionic (bosonic) flavor to the non-Abelian side corresponds to the addition of a bosonic (fermionic) column in the dual planar quiver.

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arXiv2025

A Chiral-Planar dualization algorithm for 3d $\mathcal{N}=2$ Chern-Simons-matter theories

We show that a broad class of three-dimensional $\mathcal{N}=2$ chiral Chern-Simons gauge theories admit an abelian and planar dual description. These chiral-planar dualities emerge by performing real mass deformations on known $\mathcal{N}=4$ mirror pairs, using the $\mathcal{N}=2^*$ setup to flow to chiral theories on the electric side. While identifying the correct dual vacuum is subtle due to the rich structure of the Coulomb branch, we develop a mirror dualization algorithm that streamlines this process and systematically provides the abelian-planar duals of chiral quivers.

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arXiv2024

Planar Abelian Mirror Duals of $\mathcal{N}=2$ SQCD$_3$

We propose an Abelian mirror dual for the $\mathcal{N}=2$ SQCD$_3$ that we obtain as real mass deformation of known $\mathcal{N}=4$ mirror pairs. We match the superconformal index and the $\mathbf{S}^3_b$ partition function, discuss the agreement of the moduli spaces, and provide a map of the gauge invariant operators and the global symmetries as evidence of this duality.

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arXiv2024

Star-triangle dualities and supersymmetric improved bifundamentals

Recently it was shown that mirror duals of 3d and 4d theories with four super-charges can be described by generalized quiver theories, constructed using strongly coupled SCFTs as elementary building blocks that replace and improve standard bifundamentals. In this work we study and extend the family of such improved bifundamentals and discuss the network of star-triangle dualities they satisfy. We provide a field theoretic proof of the star-triangle dualities, which only assumes the basic Seiberg dualities, using the sequential deconfinement technique.

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arXiv2024

Deconfinements, Kutasov-Schwimmer dualities and $D_p[SU(N)]$ theories

Kutasov-Schwimmer (KS) dualities involve a rank-$2$ field with a polynomial superpotential. We derive KS-like dualities via deconfinement, that is assuming only Seiberg-like dualities, which instead just involve fundamental matter. Our derivation is split into two main steps. The first step is the construction of two families of linear quivers with $p\!-\!1$ nodes that confine into a rank-$2$ chiral field with degree-$(p\!+\!1)$ superpotential. Such chiral field is an $U(N)$ adjoint in 3d and an $USp(2N)$ antisymmetric in 4d. In the second step we use these linear quivers to derive, via deconfinement, in a relatively straightforward fashion, two classes of KS-like dualities: the Kim-Park duality for $U(N)$ with adjoint in 3d and the Intriligator duality for $USp(2N)$ with antisymmetric in 4d. We also discuss the close relation of our 3d family of confining unitary quivers to the 4d $\mathcal{N}\!=\!2$ $D_p[SU(N)]$ SCFTs by circle compactification and various deformations.

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arXiv2023

Mirror dualities with four supercharges

We consider 3d N=2 non-abelian Hanany-Witten brane setups with chiral flavor symmetry. We propose that the associated field theories are quivers with improved bifundamentals, instead of standard bifundamentals. The improved bifundamental is a strongly coupled SCFT that carries one more U(1) global symmetry than the standard bifundamental. As a consequence, our proposal overcomes the long standing challenge of associating to each N=2 brane setup a gauge theory with the full rank global symmetry, allowing the study of all the usual supersymmetric observables, such as superconformal index, sphere partition function, chiral ring and moduli space. The construction passes many non-trivial tests, for instance we algorithmically prove that any two improved quivers associated to S-dual brane setups are infrared dual. The 3d N=2 mirror dualities can be uplifted to 4d dualities with 4d improved bifundamentals connecting USp(2N) nodes.

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arXiv2023

Chern-Simons-Trinion Theories: One-form Symmetries and Superconformal Indices

We study 3d theories containing $\mathcal{N}=3$ Chern-Simons vector multiplets coupled to the $\mathrm{SU}(N)^3$ flavour symmetry of 3d $T_N$ theories with Chern-Simons level $k_1$, $k_2$ and $k_3$. It was formerly pointed out that these theories flow to infrared SCFTs with enhanced $\mathcal{N}=4$ supersymmetry when $1/k_1+1/k_2+1/k_3=0$. We examine superconformal indices of these theories which reveal that supersymmetry of the infrared SCFTs may get enhanced to $4 \leq \mathcal{N} \leq 6$ if such a condition is satisfied. Moreover, even if the Chern-Simons levels do not obey the aforementioned condition, we find that there is still an infinite family of theories that flows to infrared SCFTs with $\mathcal{N}=4$ supersymmetry. The 't Hooft anomalies of the one-form symmetries of these theories are analysed. As a by-product, we observe that there is generally a decoupled topological sector in the infrared. When the infrared SCFTs have $\mathcal{N} \geq 4$ supersymmetry, we also study the Higgs and Coulomb branch limits of the indices which provide geometric information of the moduli space of the theories in question in terms of the Hilbert series.

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arXiv2023

The $SL(2,\mathbb{Z})$ dualization algorithm at work

Recently an algorithm to dualize a theory into its mirror dual has been proposed, both for $3d$ $\mathcal{N}=4$ linear quivers and for their $4d$ $\mathcal{N}=1$ uplift. This mimics the manipulations done at the level of the Type IIB brane setup that engineers the $3d$ theories, where mirror symmetry is realized as $S$-duality, but it is enirely field-theoretic and based on the application of genuine infra-red dualities that implement the local action of $S$-duality on the quiver. In this paper, we generalize the algorithm to the full duality group, which is $SL(2,\mathbb{Z})$ in $3d$ and $PSL(2,\mathbb{Z})$ in $4d$. This also produces dualities for $3d$ $\mathcal{N}=3$ theories with Chern--Simons couplings, some of which have enhanced $\mathcal{N}=4$ supersymmetry, and their new $4d$ $\mathcal{N}=1$ counterpart. In addition, we propose three ways to study the RG flows triggered by possible VEVs appearing at the last step of the algorithm, one of which uses a new duality that implements the Hanany--Witten move in field theory.

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