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Davide Gaiotto

Publications and source records attributed to Davide Gaiotto.

At least 19 recordsLinked to original sources

Interface Minimal Model Holography and Topological String Theory

We study the dynamics of 2d fermions coupled to 3d Chern-Simons gauge fields. For $SU(N)$ gauge group and fermions in the fundamental representation, the resulting interfaces are closely related to $W_N$ minimal models. We give an holographic description of the interfaces within the A-model Topological String Theory. The model has exotic integrability properties, which allow us to propose an exact holographic match of all sphere correlation functions of meson operators. This construction embeds Minimal Model Holography in String Theory.

hep-th

Free and Interacting Fermionic Conformal Field Theories on the Fuzzy Sphere

The fuzzy-sphere regularisation is a powerful tool to study conformal field theories (CFT) in three spacetime dimensions. In this paper, we extend its scope to CFTs with local fermionic operators. We realise the free-Majorana-fermion CFT on a set-up with one flavour of bosons and one flavour of fermions on the lowest Landau level with a $1/2$ angular momentum mismatch and allow conversion between two bosons and two fermions, and use a relative chemical potential as the tuning parameter. On the phase diagram, we observe two continuous transitions described respectively by a free Majorana fermion and a gauged Ising CFT. We numerically confirm the emergent conformal symmetry through the operator spectrum and the two-point correlation function of the local Majorana fermion. We further establish a correspondence between the fuzzy-sphere models and the field-theory Lagrangians, and extend it to an interacting fermionic CFT -- the super-Ising theory with emergent super-conformal symmetry.

hep-th

Categories of Line Defects and Cohomological Hall Algebras

Any four-dimensional Supersymmetric Quantum Field Theory with eight supercharges can be associated to a monoidal category of BPS line defects. Any Coulomb vacuum of such a theory can be conjecturally associated to an ``algebra of BPS particles'', exemplified by certain Cohomological Hall Algebras. We conjecture the existence of a monoidal functor from the category of line defects to a certain category of bimodules for the BPS Algebra in any Coulomb vacuum. We describe images of simple objects under the conjectural functor and study their monoidal structure in examples. We conjecture that the functor may be an equivalence of dg-categories and test the conjecture at the level of the equivariant Witten indices of the spaces of morphisms.

hep-th

D-branes and the planar limit of Chern-Simons theory I: Link invariants

We revisit the Holographic duality between $SU(N)_κ$ Chern-Simons theory and the A-model Topological String Theory. We develop a strategy to systematically compute the large $N$ saddles for correlation functions of Wilson lines in antisymmetric powers $Λ^\bullet \mathbb{C}^N$ of the fundamental representation. The mathematical structures which appear in the calculation match in detail the data of dual A-model D-branes.

hep-th

The Categorical 't Hooft Expansion

We review categorical aspects of 't Hooft's large $N$ expansion, which is expected to map any Quantum Field Theory of large matrices to a string theory. Our goal is to describe a general strategy to derive the string theory dual to given QFT, at least at the leading order in the 't Hooft expansion. The basic idea is to characterize the underlying worldsheet theory of the dual string theory as an extended two-dimensional differential graded Topological Field Theory (dg-TFT), i.e. present an $A_\infty$-category of boundary conditions ("D-branes"). A basic aspect of the 't Hooft expansion is that D-branes arise from the addition of vector-valued degrees of freedom to the QFT. We propose that formal deformations of such "fundamental modifications" must match the formal deformations of the dual D-branes, which in turn capture the $A_\infty$-category structure and thus the worldsheet dg-TFT. We discuss several systems for which a rigorous analysis along these lines is or should be possible.

hep-th

Categorical 't Hooft expansion and chiral algebras

Twisted holography captures protected aspects of well-known holographic dualities. We show how the holographic dual B-model background can be systematically derived from the 't Hooft expansion of the chiral algebras associated to four-dimensional ${\cal N}=2$ superconformal quiver gauge theories. A crucial tool is the match of planar BRST anomalies in the field theory and on the worldsheet, especially in the presence of probe D-branes. Our construction is very general and can be applied to chiral algebras which do not have a four-dimensional origin. The resulting holographic dual backgrounds are typically non-geometric and appear to be novel. We expect our strategy to have a wide range of applications to other examples of twisted holography and, potentially, weak coupling holography.

hep-th

Twisted traces on abelian quantum Higgs and Coulomb branches

We study twisted traces on the quantum Higgs branches $A_{\operatorname{Higgs}}$ of $3d, \mathcal{N}=4$ gauge theories, that is, the quantum Hamiltonian reductions of Weyl algebras. In theories which are good, we define a twisted trace that arises naturally from the correlation functions of the gauge theory. We show that this trace induces an inner product and a short star product on $A_{\operatorname{Higgs}}$. We analyze this trace in the case of an abelian gauge group and show that it has a natural expansion in terms of the twisted traces of Verma modules, confirming a conjecture of the first author and Okazaki. This expansion has a natural interpretation in terms of 3-d mirror symmetry, and we predict that it can be interpreted as an Atiyah-Bott fixed-point formula under the quantum Hikita isomorphism.

hep-th

Condensations in higher categories

We present a higher-categorical generalization of the "Karoubi envelope" construction from ordinary category theory, and prove that, like the ordinary Karoubi envelope, our higher Karoubi envelope is the closure for absolute limits. Our construction replaces the idempotents in the ordinary version with a notion that we call "condensations." The name is justified by the direct physical interpretation of the notion of condensation: it encodes a general class of constructions which produce a new topological phase of matter by turning on a commuting projector Hamiltonian on a lattice of defects within a different topological phase, which may be the trivial phase. We also identify our higher Karoubi envelopes with categories of fully-dualizable objects. Together with the Cobordism Hypothesis, we argue that this realizes an equivalence between a very broad class of gapped topological phases of matter and fully extended topological field theories, in any number of dimensions.

math.CT

Renormalization Group flow in Schur quantization

We develop a general formalism to describe the Renormalization Group Flow of Schur indices and fusion algebras of BPS line defects in four-dimensional ${\cal N}=2$ Supersymmetric Quantum Field Theories. The formalism includes and extends known results about the Seiberg-Witten description of these structures. Another application of the formalism is to describe the spectrum of BPS partices of ${\mathcal N}=2$ gauge theories with matter in terms of the spectrum of pure ${\mathcal N}=2$ gauge theories. Applications to the theory of quantum groups and to the quantization of cluster varieties are also discussed.

hep-th

Global Anomalies on the Hilbert Space

We show that certain global anomalies can be detected in an elementary fashion by analyzing the way the symmetry algebra is realized on the torus Hilbert space of the anomalous theory. Distinct anomalous behaviours imprinted in the Hilbert space are identified with the distinct cohomology "layers" that appear in the classification of anomalies in terms of cobordism groups. We illustrate the manifestation of the layers in the Hilbert for a variety of anomalous symmetries and spacetime dimensions, including time-reversal symmetry, and both in systems of fermions and in anomalous topological quantum field theories (TQFTs) in 2+1d. We argue that anomalies can imply an exact bose-fermi degeneracy in the Hilbert space, thus revealing a supersymmetric spectrum of states; we provide a sharp characterization of when this phenomenon occurs and give nontrivial examples in various dimensions, including in strongly coupled QFTs. Unraveling the anomalies of TQFTs leads us to develop the construction of the Hilbert spaces, the action of operators and the modular data in spin TQFTs, material that can be read on its own.

hep-th

Twisted M2 brane holography and sphere correlation functions

We define and compute algebraically a "perturbative part" of protected sphere correlation functions in the M2 brane SCFTs. These correlation functions are expected to have a holographic description in terms of twisted, $Ω$-deformed M-theory. We uncover a hidden perturbative triality symmetry which supports this conjecture. We also discuss some variants of the setup, involving M2 branes at $A_k$ singularities and D3 branes with a transverse compact direction.

hep-th

Aspects of $Ω$-deformed M-theory

We explore the properties of $Ω$-deformed M-theory, with particular focus on the $\mathbb{C}_{ε_1} \times\mathbb{C}_{ε_2}\times \mathbb{C}_{ε_3}$ background and coupling to $Ω$-deformed M2 and M5 brane world-volume theories.

hep-th

Combinatorial proof of a Non-Renormalization Theorem

We provide a direct combinatorial proof of a Feynman graph identity which implies a wide generalization of a formality theorem by Kontsevich. For a Feynman graph $Γ$, we associate to each vertex a position $x_v \in \mathbb R$ and to each edge $e$ the combination $s_e = a_e^{-\frac 12} \left( x^+_e - x^-_e \right)$, where $x^\pm_e$ are the positions of the two end vertices of $e$, and $a_e$ is a Schwinger parameter. The "topological propagator" $P_e = e^{-s_e^2}\text d s_e$ includes a part proportional to $\text d x_v$ and a part proportional to $\text d a_e$. Integrating the product of all $P_e$ over positions produces a differential form $α_Γ$ in the variables $a_e$. We derive an explicit combinatorial formula for $α_Γ$, and we prove that $α_Γ\wedge α_Γ=0$.

math-ph

3D TFTs from 4d ${\cal N}=2$ BPS Particles

We propose a general strategy to build three-dimensional gauge theories with four supercharges which enjoy a supersymmetry enhancement in the IR. The resulting IR SCFTs admit topological twists with particularly nice properties, as well as boundary rational chiral algebras such that the associated Modular Tensor Categories are controlled by the topological twist. The theories arise from a twisted circle compactification of four-dimensional theories of Argyres-Douglas type. We develop a novel algorithm to compute or manipulate protected quantities associated to these theories, such as ellipsoid partition functions and superconformal indices and half-indices.

hep-th

SYK-Schur duality: Double scaled SYK correlators from $N=2$ supersymmetric gauge theory

We propose a triality relating the Double-Scaled SYK model, $SL(2,\mathbb{C})$ Chern-Simons theory on a disk with an irregular singularity at the center and the outcome of ``real Schur quantization'' applied to $SU(2)$ Seiberg-Witten theory with Neumann boundary conditions. We give supporting evidence for our conjecture by establishing a precise match between a general class of correlators in all three systems.

hep-th

Semi-Chiral Operators in 4d ${\cal N}=1$ Gauge Theories

We discuss the properties of quarter-BPS local operators in four dimensional ${\cal N}=1$ supersymmetric Yang-Mills theory using the formalism of holomorphic twists. We study loop corrections both to the space of local operators and to algebraic operations which endow the twisted theory with an infinite symmetry algebra. We classify all single-trace quarter-BPS operators in the planar approximation for $SU(N)$ gauge theory and propose a holographic dual description for the twisted theory. We classify perturbative quarter-BPS operators in $SU(2)$ and $SU(3)$ gauge theories with sufficiently small quantum numbers and discuss possible non-perturbative corrections to the answer. We set up analogous calculations for some theories with matter.

hep-th

The $g$-function and Defect Changing Operators from Wavefunction Overlap on a Fuzzy Sphere

Defects are common in physical systems with boundaries, impurities or extensive measurements. The interaction between bulk and defect can lead to rich physical phenomena. Defects in gapless phases of matter with conformal symmetry usually flow to a defect conformal field theory (dCFT). Understanding the universal properties of dCFTs is a challenging task. In this paper, we propose a computational strategy applicable to a line defect in arbitrary dimensions. Our main assumption is that the defect has a UV description in terms of a local modification of the Hamiltonian so that we can compute the overlap between low-energy eigenstates of a system with or without the defect insertion. We argue that these overlaps contain a wealth of conformal data, including the $g$-function, which is an RG monotonic quantity that distinguishes different dCFTs, the scaling dimensions of defect creation operators $Δ^{+0}_α$ and changing operators $Δ^{+-}_α$ that live on the intersection of different types of line defects, and various OPE coefficients. We apply this method to the fuzzy sphere regularization of 3D CFTs and study the magnetic line defect of the 3D Ising CFT. Using exact diagonalization and DMRG, we report the non-perturbative results $g=0.602(2),Δ^{+0}_0=0.108(5)$ and $Δ^{+-}_0=0.84(5)$ for the first time. We also obtain other OPE coefficients and scaling dimensions. Our results have significant physical implications. For example, they constrain the possible occurrence of spontaneous symmetry breaking at line defects of the 3D Ising CFT. Our method can be potentially applied to various other dCFTs, such as plane defects and Wilson lines in gauge theories.

hep-th