arXiv subjects

Daniele Artico

Publications and source records attributed to Daniele Artico.

9 recordsLinked to original sources

arXiv2026

Boundaries and defects in conformal field theories at finite temperature

We consider conformal boundaries and defects in Euclidean conformal field theory (CFT) at finite temperature and infinite volume. We distinguish defects that wrap the thermal circle and defects that are localised at a point on it. In both set-ups, and for any dimension and co-dimension, we classify bulk one-point functions of scalar, vector and spin-2 primaries. We relate the low-temperature expansion of bulk scalar one-point functions to zero-temperature defect CFT data and new finite-temperature data of defect primaries. For localised defects, we derive one-point bootstrap sum rules using periodicity and the defect operator expansion. We consider several examples in free bulk CFTs: unitary and non-unitary boundary CFTs, a wrapping monodromy defect, and a localised magnetic line. We determine thermal defect CFT data in all examples. For defects wrapping the thermal circle, we compute thermodynamic observables. For localised defects, we observe a Hurwitz zeta function decomposition of one-point functions suggestive of an underlying dispersion relation.

hep-th↗

arXiv2026

Constraints on the $O(n)$ model from a negative number of flavors

Treating the number of flavors $n$ as a variable in the $O(n)$ model leads to non-perturbative constraints on the spectrum of operators. Using the duality between $O(n)$ and $Sp(-n)$, we extend these relations to negative even values of $n$ and we make them explicit by decomposing operators with general flavor structure into irreducible representations. In perturbation theory, we exploit this structure to reveal novel degeneracies in the scaling dimensions of different operators, which persist for arbitrary $n$. This allows us to derive the two-loop anomalous dimension of any $ϕ^k$-type operator from existing results without additional loop calculations. The same mechanism dictates patterns in renormalization group mixing matrices, yielding new non-renormalization results in a specific operator basis. We comment on extending this framework to relations between operator product expansion coefficients and to analogous constraints arising from evanescence under continuation in the number of spacetime dimensions.

hep-th↗

arXiv2026

New Exotic Operators in the Spectrum of Wilson Lines in General Representations

Wilson lines are fundamental probes of gauge theories. We show that, in sufficiently rich representations, they support a large new class of operator insertions. For half-BPS lines in $\mathcal{N}=4$ SYM many of these operators have the quantum numbers of the displacement supermultiplet. Their dimension-one superprimaries define natural deformations of the defect theory. By analyzing the associated beta functions, and relating them to specific OPE coefficients, we show that the deformations are marginally relevant. We support our finding with a weak-coupling computation of the four-point function of these operators for any gauge group and representation.

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arXiv2026

Analytical methods in Quantum Field Theories: from loop integrals to defect correlators

This thesis expands the available techniques at weak coupling by investigating the linear space of Feynman integrals and the role that (super)symmetry plays in reducing the number of integrals necessary to calculate correlators in the presence of a one-dimensional extended operator - the line defect. In the first part, linear relations among Feynman parametrized integrals are derived from their properties as projective forms; these relations are then tested on one- and multi-loop examples, and their connection to the algebra of polynomial ideals is uncovered. In the second part, made of two chapters, the defect CFT formed by the N = 4 super Yang-Mills theory in the presence of a Maldacena-Wilson line is studied through bulk-defect-defect and multipoint correlation functions up to next-to-next-to-leading order in the perturbative expansion at weak coupling. The investigations into this defect CFT lead to the identification of classes of integrals containing all the perturbative information necessary to compute the correlators, which turn out to be either rational functions or Goncharov polylogarithms.

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arXiv2026

Perturbative bootstrap of the Wilson-line defect CFT: Bulk-defect-defect correlators

We study the correlators of bulk and defect half-BPS operators in $\mathcal{N}=4$ Super Yang-Mills theory with a Maldacena-Wilson line defect, focusing on the case involving one bulk and two defect local operators. We analyze the non-perturbative constraints on these correlators, which include a topological sector, pinching and splitting limits, and we compute a variety of bulk-defect-defect correlators up to next-to-leading order at weak coupling, surprisingly observing that transcendental terms cancel. Additionally, we provide results in the strong-coupling regime for the first two leading orders using a mixture of Witten diagrams and non-perturbative constraints.

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arXiv2026

Perturbative bootstrap of the Wilson-line defect CFT: Multipoint correlators

We study the defect CFT associated with the half-BPS Wilson line in $\mathcal{N}=4$ Super Yang-Mills theory in four dimensions. Using a perturbative bootstrap approach, we derive new analytical results for multipoint correlators of protected defect operators at large $N$ and weak coupling. At next-to-next-to-leading order, we demonstrate that the simplest five- and six-point functions are fully determined by non-perturbative constraints -- which include superconformal symmetry, crossing symmetry, and the pinching of operators to lower-point functions -- as well as by a single integral, known as the train track integral. Additionally, we present new analytical results for the four-point functions $\langle 1122 \rangle$ and $\langle 1212 \rangle$.

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arXiv2024

Loop Tree Duality with generalized propagator powers: numerical UV subtraction for two-loop Feynman integrals

An explicit Loop Tree Duality (LTD) formula for two-loop Feynman integrals with integer power of propagators is presented and used for a numerical UV divergence subtraction algorithm. This algorithm proceeds recursively and it is based on the $\mathcal{R}$ operator and the Hopf algebraic structure of UV divergences. After a short review of LTD and the numerical evaluation of multi-loop integrals, LTD is extended to two-loop integrals with generalized powers of propagators. The $\mathcal{R}$ operator and the tadpole UV subtraction are employed for the numerical calculation of two-loop UV divergent integrals, including the case of quadratic divergences.

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arXiv2023

IBPs and differential equations in parameter space

We present a projective framework for the construction of Integration by Parts (IBP) identities and differential equations for Feynman integrals, working in Feynman-parameter space. This framework originates with very early results which emerged long before modern techniques for loop calculations were developed. Adapting and generalising these results to the modern language, we use simple tools of projective geometry to generate sets of IBP identities and differential equations in parameter space, with a technique applicable to any loop order. We test the viability of the method on simple diagrams at one and two loops, providing a unified viewpoint on several existing results.

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arXiv2023

Integration-by-parts identities and differential equations for parametrised Feynman integrals

Integration-by-parts (IBP) identities and differential equations are the primary modern tools for the evaluation of high-order Feynman integrals. They are commonly derived and implemented in the momentum-space representation. We provide a different viewpoint on these important tools by working in Feynman-parameter space, and using its projective geometry. Our work is based upon little-known results pre-dating the modern era of loop calculations: we adapt and generalise these results, deriving a very general expression for sets of IBP identities in parameter space, associated with a generic Feynman diagram, and valid to any loop order, relying on the characterisation of Feynman-parameter integrands as projective forms. We validate our method by deriving and solving systems of differential equations for several simple diagrams at one and two loops, providing a unified perspective on a number of existing results.

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