A
bstract
We study the constraints of superconformal symmetry on codimension two defects in four-dimensional superconformal field theories. We show that the one-point function of the stress tensor ...and the two-point function of the displacement operator are related, and we discuss the consequences of this relation for the Weyl anomaly coefficients as well as in a few examples, including the supersymmetric Rényi entropy. Imposing consistency with existing results, we propose a general relation that could hold for sufficiently supersymmetric defects of arbitrary dimension and codimension. Turning to
N
= (2
,
2) surface defects in
N
≥
2 superconformal field theories, we study the associated chiral algebra. We work out various properties of the modules introduced by the defect in the original chiral algebra. In particular, we find that the one-point function of the stress tensor controls the dimension of the defect identity in chiral algebra, providing a novel way to compute it, once the defect identity is identified. Studying a few examples, we show explicitly how these properties are realized.
A
bstract
We study operator insertions into 1/2 BPS Wilson loops in
N
= 6 ABJM theory and investigate their two-point correlators. In this framework, the energy emitted by a heavy moving probe can be ...exactly obtained from some two-point coefficients of bosonic and fermionic insertions. This allows us to confirm an early proposal 1 for computing the Bremsstrahlung function in terms of certain supersymmetric circular Wilson loops, whose value might be accessible to localization techniques. In the derivation of this result we also elucidate the structure of protected multiplets in the relevant superconformal defect theory and perform an explicit two-loop calculation.
Exact Bremsstrahlung functions in ABJM theory Bianchi, Lorenzo; Preti, Michelangelo; Vescovi, Edoardo
The journal of high energy physics,
07/2018, Letnik:
2018, Številka:
7
Journal Article
Recenzirano
Odprti dostop
A
bstract
In this paper we study the Bremsstrahlung functions for the
1
6
B
P
S
and the
1
2
B
P
S
Wilson lines in ABJM theory. First we use a superconformal defect approach to prove a conjectured ...relation between the Bremsstrahlung functions associated to the geometric (
B
1/6
φ
) and R-symmetry (
B
1/6
θ
) deformations of the
1
6
B
P
S
Wilson line. This result, non-trivially following from a defect supersymmetric Ward identity, provides an exact expression for
B
1/6
θ
based on a known result for
B
1/6
φ
. Subsequently, we explore the consequences of this relation for the
1
2
B
P
S
Wilson line and, using the localization result for the multiply wound Wilson loop, we provide an exact closed form for the corresponding Bremsstrahlung function. Interestingly, for the comparison with integrability, this expression appears particularly natural in terms of the conjectured interpolating function
h
(
λ
). During the derivation of these results we analyze the protected defect supermultiplets associated to the broken symmetries, including their two- and three-point correlators.
A
bstract
We study the two-point function of local operators in the critical
O
(
N
) model in the presence of a magnetic field localized on a line. We use a recently developed conformal dispersion ...relation to compute the correlator at first order in the
ϵ
-expansion and we extract the full set of defect and bulk CFT data using the Lorentzian inversion formulae. The only input for the computation of the connected correlator is its discontinuity at first order in perturbation theory, which is determined by the anomalous dimension of a single bulk operator. We discuss possible low-spin ambiguities and perform several diagrammatic checks of our results.
Alcohol consumption in the under-18 age group has been growing in recent years, leading to various health risks. Considering the problems this habit brings, the present study contributes to the ...literature dedicated to categorizing different types of drinkers. The study objective is to verify the factors associated with the intensity of alcohol use among elementary school students in the year 2015. The dataset came from the National Adolescent School-based Health Survey (PeNSE). The applied methodology was a logit model of sequential response (continuation ratio). The main results are as follows. It was found that being female is associated with a lesser chance of having consumed alcohol in the reference period, however, with a greater chance of consuming five or more doses. Economic condition and formal paid employment are positively associated with alcohol consumption, which increases with the progression of the student's age. The number of friends who drink alcohol and consumption of products originating from tobacco and illicit drugs, are good predictors of alcohol use by students. The time spent practicing physical activities increased the chance of male students consuming alcohol. The results showed that, in general, the characteristics associated with different alcohol consumption profiles remain similar but differ between genders. Intervention strategies aimed at preventing alcohol consumption by minors are suggested in order to reduce the negative effects of substance use and abuse.
Monodromy defects in free field theories Bianchi, Lorenzo; Chalabi, Adam; Procházka, Vladimír ...
The journal of high energy physics,
08/2021, Letnik:
2021, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A
bstract
We study co-dimension two monodromy defects in theories of conformally coupled scalars and free Dirac fermions in arbitrary
d
dimensions. We characterise this family of conformal defects by ...computing the one-point functions of the stress-tensor and conserved current for Abelian flavour symmetries as well as two-point functions of the displacement operator. In the case of
d
= 4, the normalisation of these correlation functions are related to defect Weyl anomaly coefficients, and thus provide crucial information about the defect conformal field theory. We provide explicit checks on the values of the defect central charges by calculating the universal part of the defect contribution to entanglement entropy, and further, we use our results to extract the universal part of the vacuum Rényi entropy. Moreover, we leverage the non-supersymmetric free field results to compute a novel defect Weyl anomaly coefficient in a
d
= 4 theory of free
N
= 2 hypermultiplets. Including singular modes in the defect operator product expansion of fundamental fields, we identify notable relevant deformations in the singular defect theories and show that they trigger a renormalisation group flow towards an IR fixed point with the most regular defect OPE. We also study Gukov-Witten defects in free
d
= 4 Maxwell theory and show that their central charges vanish.
Dual conformal invariance for form factors Bianchi, Lorenzo; Brandhuber, Andreas; Panerai, Rodolfo ...
The journal of high energy physics,
02/2019, Letnik:
2019, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A
bstract
Form factors of the stress-tensor multiplet operator in
N
=
4
supersymmetric Yang-Mills reveal surprisingly simple structures similar to those appearing in scattering amplitudes. In this ...paper we show that, as for the case of amplitudes, they also enjoy dual conformal symmetry. We compute the dual conformal anomaly at one loop for an arbitrary number of particles and generic helicities, which matches the expression of the dual conformal anomaly of amplitudes, and perform explicit checks for MHV and NMHV one-loop form factors. In the NMHV case the realisation of dual conformal symmetry requires a delicate cancellation of offending terms arising from three-mass triangles, which we explicitly check in the case of the four-point NMHV form factor.
Mellin amplitudes for 1d CFT Bianchi, Lorenzo; Bliard, Gabriel; Forini, Valentina ...
The journal of high energy physics,
10/2021, Letnik:
2021, Številka:
10
Journal Article
Recenzirano
Odprti dostop
A
bstract
We define a Mellin amplitude for CFT
1
four-point functions. Its analytical properties are inferred from physical requirements on the correlator. We discuss the analytic continuation that ...is necessary for a fully nonperturbative definition of the Mellin transform. The resulting bounded, meromorphic function of a single complex variable is used to derive an infinite set of nonperturbative sum rules for CFT data of exchanged operators, which we test on known examples. We then consider the perturbative setup produced by quartic interactions with an arbitrary number of derivatives in a bulk AdS
2
field theory. With our formalism, we obtain a closed-form expression for the Mellin transform of tree-level contact interactions and for the first correction to the scaling dimension of “two-particle” operators exchanged in the generalized free field theory correlator.
Form factor recursion relations at loop level Bianchi, Lorenzo; Brandhuber, Andreas; Panerai, Rodolfo ...
The journal of high energy physics,
02/2019, Letnik:
2019, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A
bstract
We introduce a prescription to define form factor integrands at loop level in planar
N
=
4
supersymmetric Yang-Mills theory. This relies on a periodic kinematic configuration that has been ...instrumental to describe form factors at strong coupling in terms of periodic Wilson loops. With this prescription, we are able to formulate loop-level recursion relations for planar form factor integrands, using a two-line (BCFW) and an all-line shift. We also point out important differences with the known recursion relations of integrands of planar loop amplitudes. We present a number of concrete one-loop examples to illustrate and validate our prescription for form factor integrands.
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